Slum Ecology

Buenos Aires may have the worst feng shui in the world: it is built in a flood zone over a former lake, a toxic dump, and a cemetery. Then there's the barrio perched precariously on stilts over the excrement-clogged Pasig River in Manila, and the bustee in Vijayawada that floods so regularly that residents have door numbers written on pieces of furniture. In slums the world over, squatters trade safety and health for a few square meters of land and some security of tenure. They are pioneers of swamps, floodplains, volcano slopes, unstable hillsides, desert fringes, railroad sidings, rubbish mountains, and chemical dumps—unattractive and dangerous sites that have become poverty's niche in the ecology of the city.

Cities have absorbed nearly two-thirds of the global population explosion since 1950, and are currently adding a million babies and migrants each week. Dhaka, Kinshasa, and Lagos today are each approximately forty times larger than they were in 1950. According to the Financial Times, China in the 1980s alone added more city dwellers than did all of Europe (including Russia) during the entire nineteenth century.

In this process of rampant urbanization, the planet has become marked by the runaway growth of slums, characterized by overcrowding, poor or informal housing, inadequate access to safe water and sanitation, and insecurity of tenure. UN researchers estimate that there were at least 921 million slum dwellers in 2001 and more than 1 billion in 2005, with slum populations growing by a staggering 25 million per year.