Time has an excellent article on Mumbai’s Slums.

The state government of Maharashtra, of which Mumbai (formerly Bombay) is the capital, wants to raze dozens of slums like Dharavi for redevelopment and new infrastructure as part of its multibillion-dollar plan to turn the city into a world-class financial center by 2015. No one doubts that India’s business capital needs a makeover. Bad roads and inefficient or nonexistent public transport make getting around Mumbai a nightmare; monsoon rains and clogged rivers and drains regularly submerge whole sections of the city. In areas wet and dry, however, property prices are higher than those in midtown Manhattan. But the redevelopment plans will displace up to half the 14 million to 18 million people in India’s largest city and challenge the idea that poor and rich can live side by side in a tumultuous democracy. Even the poorest in Mumbai agree that the city needs to change. But, they ask, at what cost?

Dharavi is a living slum, as big as a small city, and the slums are so special, and unique many people visit the place as a major tourist destinations, also called slum tourism. There are tourist operators and travel agents thats specially conducts slum tours in Dharavi.