(l) While megacities are renowned for pollution, they often generate a lot of money. (II) Estimates made during the past two decades suggested that most megacities would continue to increase at an alarming rate. (!!!) But contrary to expectations, more people are now leaving many of the world's (argest urban areas than are moving in. (İV) For example, the population of Sao Paulo was expected to reach 24 million by the year 2000, but fewer than 13 million live there now. (V) There is a similar situation in cities such as Calcutta, Buenos Aires and Beijing.