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CLIMATE CHANGE, DISASTER RISK, AND THE URBAN POOR
and permanent materials over time. Older slums have more owner-occupied and self-employed residents than newer, poorer settlements. However, renting and subletting from subsistence landlords, absentee landlords, developers, and rent agents is common (UN-HABITAT 2003a). Peri-urban Slums
Slums in peri-urban areas are formed by one of three processes: squatting; deterioration of public and industrial housing that created slum estates; and illegal subdivision of land with the permission of the owner, but not of local authorities. While land is less expensive than in the inner cities, the cost of transportation can be high and travel times long, making access to work, markets, and social amenities more difficult and costly. Slum estates were typically built between the 1950s and 1970s, when many cities built public housing to rehabilitate residents of center-city slums and squatter settlements with minimal services. Although the structures are relatively recent, they were built of poor materials and construction quality. Examples include “newtowns” in Cairo (Helwan, Moktam, and Shubra), Ciudad Kenedy in Bogota, large State Housing Board housing developments constructed in almost all the major Indian cities during the 1970s and 1980s, and housing for industrial workers, such as hostels and estates of small dwellings for mine workers in Southern Africa, “chawls” built for textile industry workers in Mumbai, India, and slab blocs in the former communist countries (UN-HABITAT 2003a). In illegal subdivisions, low-income households purchase or rent private land of relatively lower value at the periphery from developers that is developed without the consent of the local authorities, and hence is illegal. The developer may be a well-connected businessman or politician who has the resources and power to purchase, lay out, and allocate land. The layouts, however, may not meet official development standards. Since trunk infrastructure is limited in peri-urban locations, most illegal subdivisions have poor or no services. Housing conditions are typically better than adjoining rural areas and squatter settlements of the same age. Dwellings are mostly owner occupied, although renting also exists. Spatial Contiguity and Size
There are slums laid out contiguously that are typically either physically isolated from surrounding planned neighborhoods by canals, storm drains, railway tracks, and motorways, or may be interspersed within planned residential areas. The size of slums can also vary substantially, also affecting exposure. Although some slums are larger than many cities, medium-sized slums are more common. Kibera, in Nairobi, is a 550-acre slum with between 200,000