Negative environment of megacities
Megacities are largely a phenomenon of the developing world. It is predicted that in a few years' time, the urban population of the developing world will be twice as big as that of the industrialized countries.
If a "megacity" is defined as a city with a population of over 5 million inhabitants, then in 1950, Mexico City was the only one in the developing world to qualify for that name. Now it is the second-largest city on Earth, with a population of 20 million, and 32 more cities have become 'megacities' (by the year 2000, there will be at least 35). In 1990, the 33 largest cities comprised
Megacities now tend to be described as cities having more than 10 million inhabitants. By the year 2015, the 10 largest cities in the world will be in Asia, Latin America and Africa. While Tokyo, with 28.7 million inhabitants, is expected to be the largest and only one among the world's megacities located in the developed world, the remaining 9 will all be in developing countries: Bombay, India (27.4 million); Lagos, Nigeria (24.4); Shanghai, China (23.4); Jakarta, Indonesia (21.2); Sao Paulo, Brazil (20.8); Karachi, Pakistan (20.6); Beijing, China (19.4); Dhaka, Bangladesh (19); and Mexico City, Mexico (18.8).