1- Historical Areas of the Cities
It is applied to the areas of a city that reflect its historical-cultural values and are developed by means of an interaction between people and their environment throughout the history; while regarding formal characteristics and compositional structures, they can be distinguished from other urban areas. These areas contain the cultural treasures and historical-intangible and natural heritage of a city. Following the modernizations in the first half of the twentieth century, these areas have gone through spatial-functional transformations, and influenced by the disharmonious and rapid growth of the later decades, they have lost their initial function, and are faced with a shrinkage of social-local and economic rank. Urban poverty, identity crisis and low resilience against natural disasters are among the most important issues faced by these areas.
2- Inefficient Infill Urban Fabrics
It is applied to the areas and neighborhoods of a city that are developed around its historical core, but are considered as contemporary urban fabric. Because of physical instability, inefficiency of infrastructures, social anomalies and functional disorders, these urban areas are stagnated and obsoleted; and their shaping elements, such as superstructures, infrastructures and buildings, have become inefficient and their inhabitants suffer from numerous economic, social, cultural and spatial problems.
3- Urban Areas with Rural Backgrounds
It is applied to the areas of a city with a rural core, which due to the urban sprawl, are integrated with its existing areas. Due to the duality in formal structure and social and functional-spatial organization, these neighborhoods have experienced many disorders. Among the major problems faced by these areas, one can name: physical instability, spatial disorganizations, inefficiency of infrastructures and the lack of urban-local services as well as social-cultural issues.
4- Informal Settlements
It is applied to the areas and neighborhoods that, due to the urban sprawl and the disharmonious developments of recent decades, are formed and developed in or out of the boundaries of a city. These fabrics generally accommodate the rural migrants and under-privileged inhabitants of the city; and are emerged in or out of the city legal boundaries, beyond the formal and legal urban development planning, without authorization. These areas are also faced with numerous major issues, such as urban poverty (low income and education of the inhabitants, lack of infrastructures, services and facilities), identity crisis caused by unauthorized, chaotic and unstandardized constructions, and also very low resilience against natural disasters such as earthquake, flood and storm.
Based on the surveys carried out by the UDRC, in 91 cities with approved studies of provincial and county headquarters, more than 6.3 million people live in an area of nearly 60,000 hectares, from which 88% of these settlements are located within the boundaries of cities and only 12% are on the outskirts (mostly immediate outskirts) of cities. Based on the estimations, grounded on the results of the 2011 census, more than 11 million of the population of the country live in the informal settlements in the cities or on the outskirts.
Main Common Characteristics of the Inefficient Urban Areas (Target Neighborhoods and Areas):
- Lower Income per capita of the inhabitants than the average of the city and the higher rate of unemployment ;
- Low durability of residential units; higher population density per residential unit than the average of the city; and numerous environmental issues;
- Insufficient access to urban services and infrastructures;
- Higher rate of social anomaly than the average of the city; and the favorability of the context for such problems
- Disregarded historical identity; diminution of social reverence and rank; and thus the substitution of original dwellers of the neighborhood with other groups.