Urban Challenges: Informal Settlements, Deprivation and Congestion

Rapid urbanization in low- and middle-income countries has often outpaced the ability of governments and markets to provide affordable, serviced housing. The result is the growth of informal settlements—areas of unplanned, self-built housing where residents usually lack secure legal tenure to the land. The United Nations defines a slum household as one that lacks one or more of the following: durable housing, sufficient living space, easy access to safe water, adequate sanitation, and security of tenure. Around one billion people, roughly one in eight of humanity, are estimated to live in such conditions, and the number continues to rise as cities grow.

Two well-known examples illustrate the range of informal settlements. Dharavi, in Mumbai, India, is one of the most densely populated plac