THE tide of people pouring into megacities has turned. Against expectations, more people are now leaving many of the world’s largest urban areas than are moving in.
Estimates made during the past two decades suggested that most megacities would continue to swell at an alarming rate. Back in 1984, the population of São Paulo was expected to hit 24 million by 2000. But today, fewer than 18 million live there. Mexico City was to jump from 16 million to 26 million over the same period. But the city has grown by only 2 million, according to last year’s census, largely…
