© W. Al Muhanna, Published by EDP Sciences, 2024

1 Introduction

The phenomenon of urban sprawl represents a highly intricate urban challenge characterized by the accommodation of a substantial population possessing limited financial resources and residing in areas with elevated population density. This issue, while having a global footprint, is predominantly manifested in developing nations, underscoring its significance in urban landscapes. Urban sprawl came to the fore and proliferated during the latter half of the 20th century, primarily because of the heightened rates of migration from rural regions to burgeoning urban centers, concomitant with pervasive poverty in these countries.

The expansion of major metropolises that attract sizeable populations is instrumental to this process. The relative inefficacy of employment prospects within these cities, owing to the concentration of governmental institutions, educational establishments, scientific research centers, and the rapid emergence and clustering of diverse industries, has further compounded this situation. Simultaneously, rural migrants have been compelled to seek habitation characterized by decent living conditions. Their limited economic means, coupled with convenient access to employment hubs, contribute to their inclination to settle in the peripheries of urban centers where arable land is available.

This unplanned urbanization culminated in the haphazard development of housing units devoid of essential infrastructural amenities, including comprehensive road networks and reliable supply of electricity, potable water, and sanitation systems. Consequently, these areas have witnessed a surge in crime rates and the degradation of environmental health, thereby precipitating a cascade of issues spanning economics, society, public health, security, and other interconnected challenges [1].

The paramount challenge at hand pertains to the predicament of informal housing, an issue of considerable import in the majority of developing nations, including Syria, under prevailing circumstances; and its nexus with the underpinnings of sustainable development. Addressing this challenge necessitates active participation from all sectors of society in the conceptualization and formulation of mechanisms and strategies geared toward the advancement of informal housing from the vantage point of design. This endeavor mandates a comprehensive understanding of design standards, the requisites of the housing environment, and the intricate interplay among diverse associated disciplines, notably, urban and architectural design.

Since 2005, Syria has embraced a social market economy as a means of achieving social equity, in tandem with sustaining robust economic growth. Urban policies have incorporated principles of sustainable development into urban planning and housing. Concepts such as intensification, energy efficiency, and mixed use have assumed central positions and have been accorded heightened priority in housing policy.

Within the context of our case study situated in Damascus, extant policies aspire to encompass the marginalized areas under consideration. Numerous programs and policies, some of which have been under examination or have been actively implemented for more than a decade, have employed a diverse array of approaches. Two primary methodologies can be discerned. The first approach centers on the rehabilitation and organization of informal areas at the urban level, guided by national laws and policies. The second approach involves attracting investors to instigate the redevelopment and enhancement of these areas, potentially involving the relocation of current residents, either within the vicinity or to alternate locations. This research seeks to appraise the alignment of these policies with the dimensions of sustainability during the process of elevating and nurturing informal housing, while concurrently exploring the novel possibilities that these policies can engender for the creation of more sustainable urban areas.

1.1 Study area (City of Damascus)

The transformations undertaken by Damascus over the last four decades represent a considerable departure from its ancient historical trajectory. The period 1970–2010 witnessed a remarkable expansion of Damascus, akin to the patterns observed in numerous densely populated metropolises in the developing world. This unparalleled urban growth engendered a novel urban reality, most notably characterized by a pronounced surge in population density within both the city's central and peripheral precincts.

Empirical data substantiates the assertion that by 2010, the population of Damascus had swelled to an estimated 1,625,800 inhabitants. In reality, the city hosts an even larger population, particularly during daytime hours, when innumerable individuals traverse their borders for work and educational pursuits, resulting in a continuous influx and efflux of people during daylight hours. Moreover, a substantial proportion of residents hailing from other provinces choose to reside in Damascus, while retaining their official domicile registrations in their respective home provinces. This marked population escalation can be largely attributed to migratory movements and natural demographic growth, culminating in increased birth rates between 1970 and 2010 [2]. (see Fig. 1 for a graphi graphical representation).

Informal settlements within the urban fabric of Damascus can be regarded as a manifestation of the adverse facets inherent in the realm of urban planning and the trajectory of Syrian property and housing policies during the preceding five decades [4]. Since the 1960s, these areas have posed an intricate conundrum for housing policies, with their spatial footprint progressively expanding since the 1970s, primarily propelled by the confluence of domestic and international migratory movements triggered by the displacement of rural populations and emergence of regional conflicts. Beginning in the 1980s, the proliferation of unauthorized construction activities experienced a heightened intensity, largely attributable to the deficiency of robust urban planning regulations, the repercussions of unsustainable demographic expansion, and the acceleration of rural-to-urban migration dynamics [5]. (See Fig. 2 for a visual representation of this phenomenon).

Currently, although the identification of informal settlement areas within the urban structure of Damascus is conceivable, precise demarcation, quantification, and geographic location of these areas remain challenging. These areas are typically characterized by two primary designations [7]:

• Informal (Disorderly) Settlements.

• Collective Violations.

It is worth noting that the legal delineation of the perimeters of these areas predominantly centers on the legality of the constructed buildings within them rather than the areas themselves. (Refer to Fig. 3 for visual representation).

Unauthorized buildings (illegal construction) are structures built without permits, and they are the most common occurrences in informal areas. These structures do not comply with building regulations and are often violated within official zones (e.g., enclosed balconies, increased building heights, and added pitched roofs). When identifying informal settlement areas, we usually refer to areas of collective violation (i.e., comprehensive non-compliant areas).

Fig. 1 Population growth in Syria and Damascus between 1960 and 2016–Source: [3].

Fig. 2 Distribution of informal settlements on the administrative borders of Damascus City − Source: [6] Based on Geographic Information Systems (GIS) programs.

Fig. 3 Unregulated Informal Settlements on the slopes of Mount Qasioun in Damascus City − Source: Google Photo.

1.2 Literature review

The phenomenon of informal housing has been denoted by an array of terms, including unofficial settlements, illegal clusters, colloquially referred to as ‘tin cities,' ‘‘irregular towns, ‘‘shanty housing,” ‘shack towns,' among others. The delineation of informal housing areas is contingent on the unique sociocultural, economic, and environmental contexts of individual societies, signifying varying priorities and essential requirements for the sustenance of these areas across different geographical locations.

This study undertakes a comprehensive review of pertinent theoretical and scholarly research to establish a nexus between informal housing and sustainability. These investigations encompass an exploration of the interrelation between informal housing and the overarching framework of sustainable development as well as an examination of the policies enacted to address this phenomenon. Additionally, this study assimilates the seminal literature that defines and characterizes the concept of informal housing and its associated locations. A selection of these seminal works is presented below, as referenced in the following sections.

1.2.1 Literature review related to the concept of informal settlements

The 19th century, considered a pivotal epoch within the annals of history, witnessed the emergence of the concept of 'impoverished neighborhoods' encapsulated in written discourse. As the century approached its denouement, these neighborhoods were typified by a definition signifying their status as “streets or courts, positioned in locales on the periphery of towns or cities, predominantly inhabited by individuals characterized by the lowest income levels or extreme poverty, thereby resulting in tightly clustered thoroughfares and a notably substandard quality of life [8]”.

Informal settlements constitute a multifaceted domain encompassing diverse connotations and encapsulating areas that have organically evolved beyond the purview of established legal frameworks and comprehensive urban planning. These settlements frequently encroach on state-owned properties and are marked by a conspicuous absence of fundamental infrastructure and services, giving rise to a gamut of societal quandaries that inherently impinge on security and safety. Within the precincts of these settlements, issues such as impoverishment, unemployment, and criminal activities are pervasive, with repercussions extending not only to the settlements themselves, but also exerting influence on their immediate environs.

To illustrate, in the examination of the typology and prevalence of criminal activities within informal settlements, a study conducted in Kenya by Teresia in 2023, under the title “Crime Mitigation Strategies Utilized in Slum Areas of Nairobi, Kenya,” scrutinized four discrete areas characterized by informal habitation to assess the incidence of criminality. The aggregate findings of this investigation brought to the fore the prevalence of various criminal activities including illicit alcohol consumption (26%), public theft (19%), robbery (18%), and other forms of theft (12%). It is noteworthy that theft emerged as the most widespread transgression in Kibera (25%) and Mathare (24%), while Mukuru (43%) and Korogocho (23%) witnessed a notable incidence of public theft [9].

The primary impetus for the emergence of informal settlements, and consequently their subsequent classification, resides in the accelerated pace of urbanization, which engenders transformative dynamics across sociocultural, economic, and environmental spheres. However, pronounced socioeconomic disparities stemming from urban expansion exacerbate poverty. The mushrooming of impoverished neighborhoods finds its genesis in the wake of rapid urbanization, which magnetizes jobseekers from diverse regions. The inability of government bodies to provide adequate housing for the entirety of their low-income denizens is a pivotal factor underpinning the proliferation of marginalized neighborhoods. Most notably, the emergence of substantially impoverished neighborhoods can be ascribed to lacunae in urban planning and the complex tapestry of social and communal dynamics [10].

Consequently, indices of societal well-being constitute a nexus that hinges on the interplay between three fundamental and interconnected dimensions: the agency of individuals and their interactions within physical spaces, broader environmental contexts, and overarching structures that govern the symbiotic relationship between people and their surroundings. These dimensions collectively form an indispensable framework for establishing a symbiotic relationship between impoverished neighborhoods and the overarching facet of well-being, as these neighborhoods encapsulate the synthesis of people, environments, and their multifaceted interactions. Thus, the formulation of an efficacious strategy aimed at ameliorating the well-being of impoverished neighborhoods necessitates a thorough comprehension and delineation of these neighborhoods, complemented by meticulous operationalization of the concept of well-being.

In this context, [11] underscores that the emergence, growth, and categorization of informal settlements, along with their shared characteristics, precipitate profound deliberations concerning sustainable development and its efficacy within these domains. Additionally, it explores an array of policies inextricably linked with the pursuit of sustainable development goals, all of which are designed to enhance and foster the overall well-being of areas characterized by informal settlement.

1.2.2 Literature review concerning the sustainability of informal settlements

Kalyanasundaram provides an extensive exposition on sustainable development within informal areas, with a specific focus on livelihood concerns, enhancing the quality of life of residents, and the collaborative efforts of urban planners to attain optimal housing standards in these areas. The central premise is that sustainable development within informal settlements is attainable through the perpetuation of self-sustaining activities, as opposed to sporadic governmental interventions and inequitable policies [8].

In a pragmatic study conducted by a team of researchers pertaining to the advancement and transformation of an informal settlement area in Beirut [12], a sustainable developmental strategy was delineated. This strategy outlines a systematic approach that leads to holistic advancement within the region while simultaneously upholding human rights and discharging the civic responsibilities of the city. The proposed methodology for enhancing informal settlements relies on innovative tools designed to support governmental bodies and municipal councils in addressing and resolving the myriad challenges intrinsic to informal areas. The primary objectives of this framework include managing the ramifications of swift urbanization and the concomitant growth of urban populations, thereby mitigating the perils associated with habitation in precarious locations.

One illustrative example of innovative tools for the amelioration of impoverished neighborhoods involves their pivotal role in the realization of sustainable development. This entails the establishment of urban environments devoid of impoverished neighborhoods, achieved through a diagnostic examination of the central issues afflicting these areas and the concomitant inadequacy of spatial access and essential services. This approach emphasizes the integral role played by local communities and municipal authorities in fusing technical expertise with localized aspirations for urban development that align harmoniously with specific contextual requirements [13].

Leveraging these tools is essential in formulating novel strategies for projects that focus on the development of informal settlements. This strategy is predicated on identifying common ground between organized urbanism and informal settlements, while concurrently addressing housing challenges stemming from the rapid expansion of the population without encountering the complications that typically arise in informal areas. The ultimate objective is to realize sustainable housing development based on the concept of a self-built environment [14].

2 Materials and methods

The scientific methodology employed in this study is rooted in a comprehensive review of the theoretical literature pertaining to the sustainability of informal housing areas, complemented by the use of diverse research methods. The data used in this study were comprised of two distinct datasets, encompassing primary and secondary sources.

Primary data were obtained through immersive field observations and direct interviews conducted during site visits and engagement with residents. In parallel, secondary data were qualitatively extracted from a wide array of sources, including books, scholarly journals, online repositories, and aggregated data on informal residential areas in Damascus. These data were sourced from various statistical references and maps provided by Geographic Information Systems (GIS), and subsequently subjected to rigorous analysis and integration.

Consequently, the practical methodology underpinning this study was structured into two core phases. The initial phase involved an in-depth analysis of informal settlements and their sustainability. The subsequent phase entailed a comprehensive examination of the proliferation of informal settlements within Damascus's spatial confines. This was achieved by acquiring primary data and effecting a cartographic delineation of informal housing areas in Damascus, based on GIS-derived cartographic representations. These areas are typically arranged in a belt-like configuration, encircling the administrative boundaries of the city and at times encroaching upon or permeating certain vacant spaces within these boundaries. The pursuit of sustainability within these areas is contingent on the execution of rehabilitation, enhancement, and advancement initiatives, that are intrinsically linked to broader aspirations to foster the overall sustainability of the city. Therefore, the discourse centers on the formulation of innovative and holistic solutions, which constitute the foundation of the city's vision for addressing the challenges posed by informal housing areas. The plan is structured around a sequence of four consecutive stages, each geared toward creating a conducive environment for the facilitation of developmental processes aimed at achieving enhanced sustainability. It encompasses strategic policies that delineate rehabilitation programs for informal housing areas in Damascus (Tab. 1).

3 Results

Many scholars and researchers who have delved into the phenomenon of informal housing perceive it as emblematic of non-official residential developments, predominantly arising from encroachment on state-owned lands and the erection of residential structures primarily situated on the peripheries of urban centers. The term ‘informal housing’ is used to denote abodes established on extensive tracts of agricultural land through unsanctioned parceling and construction, devoid of requisite permits. These areas are inherently deficient in essential infrastructure, services, and organized layouts. Nevertheless, they collectively share a common characteristic: construction and developmental endeavors are spearheaded by families and primarily contingent on self-initiated efforts [15].

These areas are, classified through various methodologies based on construction attributes and, the distinctions between public and private properties, and the interpretation of these classifications constitutes a pivotal axis in delineating the requisite phases aimed at attaining the zenith of sustainability within informal regions.

3.1 Classification of informal housing patterns

Informal areas can be classified according to the levels of land ownership upon which they are established, the method of construction, access to services and basic infrastructure, the financial and economic capacities of their inhabitants, and their potential for growth, or based on the aforementioned criteria. Each classification method determines how to halt the expansion or identify intervention methods to enhance the environment.

3.1.1 Classification of informal areas based on land ownership status

Informal areas can be classified according to land ownership and the nature of land usage as follows:

• Informal areas are built on land owned by individuals with legal ownership documentation; however, these lands are neither planned nor compliant with building laws.

• Informal areas are established on lands owned by individuals with stable property ownership; however, these lands are agricultural and are prohibited from construction, lacking planning or compliance with building regulations [16].

• Informal areas are established on state-owned lands, but the occupants have settled in a squatting manner and their status has been regularized [17].

• Informal areas are established on state-owned land where construction is not permitted, and their ownership is not regulated by entities other than the state.

According to the aforementioned classification, the intervention methods for development are more restricted in the first type, and progress to less difficulty in the second and third types. The difficulty level decreased in the fourth type. However, it was evident that all four cases were informal settlements that required varying degrees of intervention.

3.1.2 Classification of informal areas by construction method

With rising construction costs, buildings have become an economic investment for individuals and communities. It has become a tangible reality and contributes to solving the problem of providing housing for some families in a specific economic and historical context in which the state has failed to provide suitable housing. Consequently, the cost of these constructions and the compensation for those involved in forceful and decisive interventions should be considered.

Therefore, informal areas can be classified based on construction methods [18]:

• Shelters are built using mud, tin cans, wood, and other materials (unsafe and unhygienic).

• Makeshift structures are built with load-bearing walls of red brick or stone, and concrete roofs (relatively safe).

• Makeshift structures were built using a multistory concrete structural system (safe).

• Makeshift structures are built as towers, reaching heights of up to 12 stories and sometimes more (potentially unsafe structurally).

3.1.3 Classification of informal areas according to their growth potential and expansion

This classification focuses on halting the growth and containment of informal areas and preventing their expansion to curb exacerbation of the problem. Informal areas are categorized based on their growth potential (Hassan, 2009):

• Saturated Informal Areas: Surrounded by other uses, such as industrial zones or other adjacent informal areas; these are considered saturated pockets with limited horizontal growth potential but with the possibility of vertical expansion.

• Peripheral Informal Areas: These areas border other zones from one or multiple sides, adjacent to agricultural, urban, or desert areas, and have the potential for horizontal expansion in a specific direction.

• Outskirt Informal Extension: Located beyond village limits, these areas are open spaces on agricultural lands, adjacent to or along major traffic routes, and are prone to horizontal expansion and spontaneous sprawl.

3.1.4 Classification of informal areas based on their infrastructure networks

Some areas can be classified based on the extent of public utility services such as water, sewage, electricity, gas, and telephone networks [19]:

• Informal areas are deprived of all public utility networks (owing to narrow streets and alleys that prevent access to these facilities).

• Informal areas with access to water and electricity connections.

• Informal areas enjoy connection with water, sanitation, electricity, natural gas, and telephones.

• Informal areas where residents have created water and sanitation networks through self-effort.

3.2 Slums and classifications in Damascus

At present, an estimated 38% of the population of Damascus has established residences within these localities, spanning 52% of the urban expansion of the city. Most inhabitants have constrained financial resources and possess rural origins, inhabiting substandard residential enclaves dispersed throughout different quarters of the urban landscape. Informal settlements encompass approximately 50 distinct clusters in the broader Damascus region, 37 of which are situated within the city of Damascus. According to the prevailing legal criteria, these areas exist in an entirely unauthorized state and are designated as informal housing regions [20]. Notable among them are Ash Al Warwar, Tishreen District, Al-Qaboun, Mazzeh 86, Al-Hajar Al-Aswad, At-Taqaddum, At-Tadamun, Az-Zahira Al-Jadida, Daf Al Shouk, Douayle'a, At-Tabaleh, Al-Kabbas, Ad-Dahadeel, Al-Qadam, Jaramana Camp, Palestine Camp, Yarmouk Camp, Jebel Al Riz, and additional informal suburban areas adjacent to Damascus, which fall under the jurisdiction of the RIF Dimashq Governorate [21].

Informal regions are characterized by intricate urban configurations, haphazards, and spontaneous growth. Nevertheless, they may exhibit a layout resembling a chessboard or a semi-chess structure, characterized by principal perpendicular thoroughfares, encircling residential blocks partitioned by secondary roadways, typically spanning a width of approximately 20 to 25 m, with no standardized length.

The architectural structures within these regions are typically of low elevation, predominantly restricted to two stories, whereas single-story constructions are infrequent in the later developmental phases. Multistory edifices, if present, are predominantly situated along the primary thoroughfares. The degree of urbanization varies across these areas and is inherently correlated with the age of their establishment, with the percentage of urbanization rising in tandem with the maturity of neighborhoods. In certain areas, the degree of urbanization can reach up to 90% of the overall area, nearly obliterating public spaces, squares, gardens, sports facilities, and other communal amenities. These localities routinely suffer from a dearth of public educational, cultural, healthcare, and recreational services, that are often wholly absent.

Informal housing areas are characterized by a multitude of urban predicaments, encompassing issues related to overpopulation, utilization of substandard construction materials, inadequate ventilation and sunlight exposure, and erection of structures in unsuitable locales, frequently failing to conform to established health and engineering standards. Buildings are typically situated in close proximity to one another, separated by narrow alleyways, measuring approximately 2–3 m in width, thereby diminishing both ventilation and exposure to natural light.

These areas grapple with a paucity of fundamental services including water supply, sanitation facilities, and telecommunication access. An estimated 85% of the population residing in informal areas grapples with impoverishment and a limited income. Informal housing areas exhibit divergent shapes and characteristics for various reasons behind their establishment.

To facilitate their examination, these areas were categorized based on the configuration and ownership status of the land.

3.2.1 Building violations on agricultural land

In Damascus involves discrepancies in privately owned agricultural lands located on the outskirts of the city. These violations are lawful due to land ownership documentation but unlawful due to the change in land use from agricultural to residential. They can be classified into two groups.

• The first group includes violations by individuals with limited incomes and features local, urban, social, and economic characteristics. These structures were constructed without municipal permits; however, their engineering conditions were acceptable [20]. Examples of these neighborhoods include Al-Lawan (Kafr Sousa), Tishreen, Al-Qaboun, At-Tabalah, Ad Dweilaa, At-Tadamon, and Damir.

• The second group encompasses violations by wealthier classes. These structures possess characteristics that diverge from the local culture and demonstrate higher financial costs. They comply with good engineering, health, and aesthetic standards such as the Kuwaiti Building (Sehnaya), Yafour, and As-Saboura.

3.2.2 Building violations of state properties

In Damascus may have arisen because of inhabitants' initial transition to real estate trading. They often carve out land from state properties and sell it to new migrants. The most notable informal areas created around Damascus included Mount Arz, Wadi Al-Mashariq, Mazzeh 86, Sabina Camp, Bibila, and Aish Al-Warwar. Their prominent characteristics include encroachment on engineering infrastructure, such as water, electricity, and sewage; non-compliance with health and engineering standards; and low individual income.

3.2.3 Building violations along the urban axes of the city's neighborhoods

Exhibited a reasonable level of health standards and architectural elements, meant to blend somewhat with the environment and plan for the area. One of the primary reasons for their emergence was the lack of a comprehensive urban plan for Damascus.

The key areas of informal housing along the urban axes include informal settlements at the end of the Salehiya Axis on Mount Qasioun (Rukn al-Din) − Shurah, Msatabah, and Marrabat in the Muhajireen neighborhood, as well as the upper neighborhoods of Rukn al-Din [20].

Informal housing areas encompass residential regions with unlicensed buildings, whether established in violation of the urban characteristics designated in the general regulatory plan for Damascus in 1986 or earlier. This could include areas designated as agricultural, green, or industrial zones or regions where building permits are difficult owing to a lack of necessary planning conditions (Fig. 4).

The uncontrolled expansion of informal settlements in Damascus, particularly on its periphery, transformed agricultural land into residential areas. This has led to a distortion of the city's overall urban plan, resulting in urban and housing problems. This expansion obstructed the execution of government housing projects, because part of the planned area was occupied by these settlements. It has also caused transportation issues owing to the narrow streets in these informal expansions, preventing the use of traditional transportation means such as buses, minibuses, and electric transportation, such as metros and trams, as informal buildings are densely packed, leaving insufficient space for transportation routes.

Therefore, sustainable solutions for informal settlements must initially involve their classification, as general classifications highlight the fundamental problems that lead to the emergence of such areas.

Fig. 4 Patterns of informal housing in the city of Damascus and its vital surroundings − Source: [3].

3.3 Sustainable policies to improve informal housing areas

Issues precipitating the proliferation of informal housing have exhibited notable variations among countries, making the formulation of standardized policies for their resolution a formidable challenge. As a result, governments have proffered a multitude of solutions, policies, and hypotheses to ameliorate these neighborhoods. These remedies encompass a spectrum ranging from short-term measures involving the identification of underlying causes to the pursuit of logical solutions, such as judicious state investment allocation, which could be achieved through the establishment of new attraction centers in the form of towns or villages, thereby mitigating rural-to-urban migration [22].

Furthermore, policies have been embraced to foster the development of such neighborhoods and settlements, guided by the prioritization of available resources and local circumstances. It is imperative that this issue be managed in a methodical and strategic manner, encompassing all aspects and implications over the long term, to enhance the effectiveness and impact of the process. Consequently, the methods for resolving these challenges diverge, including complete or partial removal, redevelopment, rehabilitation, and containment. While these methods are recognized as conventional practices on a global scale, there is a growing awareness worldwide of the imperative to adopt sustainable development approaches in response to environmental issues, such as climate change, global warming, and resource depletion arising from human activities.

To improve living conditions in informal areas, a multidimensional approach that encompasses the economic, environmental, social, and cultural dimensions is indispensable. These measures align with the objective of fostering sustainable development within impoverished urban neighborhoods and striving to establish economically resilient urban communities that are culturally and socially recognized for their access to essential services and urban amenities, thereby ensuring that residents have a sense of ownership of their residential areas [23]. Additionally, sustainable development serves as a crucial means to bring about substantial transformation in developing nations, affirming the necessity of sustainable development for impoverished neighborhoods [24].

The merit of the development goals lies in providing a comprehensive framework to address the reality of informal areas within urban regions rather than focusing on isolated and disjointed aspects. This perspective acknowledges that the issues plaguing informal and organized urban areas are interconnected and necessitate integrated solutions. Access to essential infrastructure facilities, effective waste management, potable water supply, and energy resources is pivotal for promoting good health, reducing the prevalence of diseases, and alleviating poverty. These elements are essential to economic development and equity. To achieve these objectives, planning and execution must be multidimensional, and require governments to possess adequate financial, human, and institutional resources. The process of addressing, improving, and developing informal areas, as described earlier, should not diverge from the pursuit of sustainable development goals; rather, it should be an integral component of comprehensive urban strategies and policies [8]. Moreover, sustainability can profoundly impact the approach to these issues, particularly when the evaluation of work considers environmental preservation, aligning with sustainable development goals, with a particular emphasis on poverty alleviation.

In the context of Damascus, the Syrian government's directives for the development and upliftment of informal housing areas were informed by the Rio de Janeiro Conference for Sustainable Development, which underscored the need to merge physical development with economic and social development plans through institutional strengthening [25]. This approach incorporated community engagement, involvement of non-governmental organizations, and participation from the private sector.

Hence, government policies were framed within a comprehensive and integrated framework that encompassed physical, social, and economic development; offered sustainable solutions; and aspired to assimilate informal communities into planned and organized urban centers. This policy was centered on improving infrastructure, ensuring tenure security, and augmenting employment opportunities through small-scale financing initiatives. Thus, decentralization, good governance, tenure security, the development of social networks, and community involvement constitute vital components of a comprehensive approach to the development and sustainability of informal housing areas [26].

Two distinct approaches and methodologies were adopted to enhance informal housing. The first is a modern approach, typically characterized by the clearance and redevelopment of old areas into towering standardized edifices, as previously mentioned. The second approach is organic, wherein informal settlements are transformed into rejuvenated community-oriented dwellings with the provision of essential infrastructure facilities, the establishment of economic activities, and the preservation of the social fabric within these areas. Resolving the debate between these two approaches is a formidable task because of the lack of data on their impact on the social, economic, and cultural status of low-income individuals [10]. Additionally, relocating families to distant locations within a city can lead to economic disruptions and social dislocations among the residents of informal settlements [27]. Therefore, it is imperative to establish sound policy frameworks at the national, regional, and international levels rooted in poverty-oriented development strategies that consider gender disparities, thereby supporting accelerated investment in poverty alleviation measures. This will be discussed in the case study of Damascus concerning government policies addressing informal housing issues.

In this context, the Syrian government has adopted a national program to upgrade the environment and informal housing areas in Damascus and in various regions across Syria. Through this program, a set of principles was established based on the development goals and a range of technical standards considering safety levels in the targeted areas. This was clarified through the systematic plan of the national program for the advancement and rehabilitation of informal housing areas, as shown in Figure 5.

Fig. 5 National program for the advancement and rehabilitation of informal housing areas − Source: [26].

4 Discussion

Like many other cities suffering from the deterioration of informal housing, Damascus formulated policies to address these areas based on the objectives of sustainable development, as highlighted in the research. The study proved that the goals of sustainable development express the necessity of achieving social justice and ensuring decent housing for all citizens, especially those living in informal settlements where essentials of life are lacking. Based on this, the policy implemented in Damascus directed urban planners to deal with these areas to reach suitable living communities and acquire local economies that established a form of equality between them and the inhabitants of organized urban areas. This allows the potential to achieve sustainable self-development in these informal areas through self-sufficiency, in addition to fundamental government intervention in the processes of improvement and advancement.

A national program to enhance these areas has been outlined. This program is based on a specific plan for social housing at the national level within the housing strategy, and does not solely focus on real estate investment and development, which leads to rising housing and land prices. To achieve this, the National Program for Advancement and Rehabilitation was founded based on a set of principles and standards, which can be summarized as follows.

Principles of the national program for advancement and rehabilitation

• Dividing informal housing areas according to their reality and taking all necessary steps to remove violations in phases.

• Allowing for the adjustment of the organizational nature of the informal settlement area.

• Providing alternative housing for violators that correspond to non-compliant residences.

• Reclassifying areas designated as informal settlements based on standards related to construction safety, urban and environmental suitability, and regulatory compliance [26].

• Advanced technology should be adopted in the processes of surveying, documenting, and classifying existing informal housing areas, which will become urban rehabilitation areas.

• Providing appropriate infrastructure and ensuring adequate health and educational services.

• Encourage and financially support non-governmental organizations to play a more effective role in managing the development of these areas.

Regarding the standards, adoption was based on safety criteria according to the degree of risk, and they were classified into four levels, as indicated:

• First degree: Areas exposed to conditions that threaten human life, such as areas prone to landslides, geological hazards, and areas susceptible to flooding.

• Second degree: Areas with residential units suffering from inappropriate construction elements, such as walls or roofs built with unsuitable materials, collapsed or cracked structures, or built on unsuitable land.

• Third degree: Areas posing a threat to public health, lacking access to clean drinking water or proper sanitation networks, affected by industrial pollution, or situated under high-tension power lines.

• Fourth degree: Areas where residents lack stable ownership. These areas were divided into those built on state-owned and government-owned lands.

By implementing this program to improve informal settlements, it is possible to make this treatment sustainable to a great extent. However, it is important to no neglect the rehabilitation of human elements within these policies. This can be achieved by defining the importance of the sustainability of their area, how to work on its development, and involving residents in the management processes by offering support and advice.

5 Conclusions and recommendations

The strategy applied in Damascus to improve informal housing partially relies on the aspects associated with sustainable development. However, its execution requires more seriousness in dealing with this reality, along with a committed adherence to the specified timeline. This necessitates the application of a dual strategy that rests on preventive policies to reduce the spread of informal settlements, and curative policies that require direct intervention in these areas for their enhancement. Each of these policies relies on the following criteria.

• Preventive policy requires the achievement of balanced developmental policies across all Syrian provinces to alleviate the severity of migration, the primary cause of the formation of these areas on the outskirts of Damascus. Encouragement of improved living conditions and increased individual capacity to purchase organized housing at reasonable prices are integral, as they boost the private sector's involvement in implementing housing policies in the city.

• Curative policy demands a specialized study of each area individually, and data collection concerning the infrastructure and service aspects provided. Direct engagement in informal settlements involves increasing the level and quality of the facilities and services. It also emphasizes community involvement in finding solutions, as treatment aims to improve the quality of life of families residing in these areas. This policy is linked to the study of unemployment indicators and the state of education and health sectors.

Acknowledgments

The author sincerely thanks Prof. Manuel Correia Guedes, Instituto Superior Técnico Department of Civil Engineering and Architecture, and the Global Platform Scholarship for their invaluable administrative and technical support throughout this research. Special thanks are extended to my family and friends in Syria for their generous contributions, including the provision of the materials and resources essential for the success of this study.

Funding

This research was supported by a Global Platform scholarship that provided financial assistance to the authors. The author expresses gratitude for this support, which was essential for the completion of the research.

Conflicts of interest

The author, Wael Al Muhanna, declares no conflict of interest related to this publication. There are no financial relationships with any organization that sponsorts this research. The author confirms full control over all primary data and provides access to the data for journal review, if requested. No other conflicts of interest, personal or professional, are present.

Data availability statement

Research data supporting this publication are available from the NN repository at www.NNN.org/download/.

Author contribution statement

Wael Al Muhanna was responsible for this manuscript's conceptualisation, methodology, data collection, analysis, and writing. The author reviewed and approved the final version, ensuring that all responsibilities were fulfilled under the journal's requirements.

References

All Tables

All Figures

	Fig. 1 Population growth in Syria and Damascus between 1960 and 2016–Source: [3].
In the text

	Fig. 2 Distribution of informal settlements on the administrative borders of Damascus City − Source: [6] Based on Geographic Information Systems (GIS) programs.
In the text

	Fig. 3 Unregulated Informal Settlements on the slopes of Mount Qasioun in Damascus City − Source: Google Photo.
In the text

	Fig. 4 Patterns of informal housing in the city of Damascus and its vital surroundings − Source: [3].
In the text

	Fig. 5 National program for the advancement and rehabilitation of informal housing areas − Source: [26].
In the text