Current population: 19.2 million
The commercial capital of India is also home to Bollywood, one of the largest film producers in the world. Mumbai has grown tremendously following India's economic liberalization in 1991, but its population explosion has left an estimated 60% of its 19.2 million people living in slums. Waves of migrants have built low structures of concrete, corrugated metal and cardboard on land that has since become valuable. The government wants to raze the slums, move millions of poor people to high-rise buildings and let developers build expensive flats. It's a plan that has many of Mumbai's residents crying foul as they are forced from their homes.
Next New York City