An ‘Informal’ or ‘squater’ Settlement exists where housing has been created in an urban or peri-urban location without official approval. Informal settlements may contain a few dwellings or thousands of them, and are generally characterized by inadequate infrastructure, poor access to basic services, unsuitable environments, uncontrolled and unhealthy population densities, inadequate dwellings, poor access to health and education facilities and lack of effective administration by the municipality. In the urban system of Iran, informal settlements are one of the important issues. This is especially important in the large cities,an example of which can be found inthe city of Mashhad.

This city is the second largest city in Iran, and has gone through a rapid physical and population growth in recent years.  Part of this growth has happened in the informal settlements around the city.  Studies show that Mashhad city currently has 42 informal settlements with a population of 804000 in 6354 hectares, which make uo 33% of the city’s population and 22% its total area. Theseneighborhoods have undesirable housing conditions.Furthermore, it is important to note the unfavorable economic conditions of the residents in these neighborhoods , and the low-income immigrants which shape part of its population.

The international studies on informal settlement improvement indicate that the downsizing of the dwelling is an important step in this regard. Correspondingly, the downsizing of the dwelling is defined as providing the adequate space  with the application of a minimum of resources, which would ensure the physical and spiritual wellbeing within a satisfactory domestic environment.

Success rate in this approach hinges on social, economic and natural conditions in different contexts. An important aim in this study was to identify the priorities in the downsizing process of the dwelling in informal settlements of Mashhad city.The research method in this study is descriptive and analytic. Primarily, the research team studied features of informal settlements, downsizing policies of the dwellings and their relevant criteria. Subsequently, features of informal settlement in Mashhad were identified. Natural indicators were obtained from spatial information layers and social and economic indicators of socio-economic databases in Mashhad.

In the next phase of the research, ARC-GIS software was applied in order to establish a spatial database for the informal settlements. The 14 criteria were selected from the characteristics of these communities which include the social (population, household size, and ethnic diversity includingTurkish, Kurdish, Luri, Turkmen, and Arab), the economic (income and land price), and the  natural (topography, distance from the fault, and from the watercourse). Then, informal settlements were prioritized, using multiple criteria spatial decision of the supporting methods. This system is composed of spatial and multiple criteria software.

Due to the large  population and vast area of  informal settlements in Mashhad city, it is important to take advantage of all the potentials to improve the quantity and quality of housing conditions. In this regard, the potentials of the private sector is one the factors worth noting.The results show that the downsizing process in informal settlements of Mashhad should be based on a categorized priority ranking among the squatters, and should be supported by pertinent supporting programs.

In this regard, Golshahr, Sheikh Hassan, Baze Sheikh and Shahid Rajai should be considered as priorities for the downsizing programs.