Dharavi (Hindi and Marathi: धारावी; Portuguese spelling Daravi British Anglicised spelling Darravy, Dorrovy) is a slum and administrative ward, over parts of Sion, Bandra, Kurla and Kalina suburbs of Mumbai, India. It is sandwiched between Mahim in the west and Sion in the east, and spread over an area of 175 hectares, or 0.67 square miles (1.7 km2). In 1986, the population was estimated at 530,225, but modern Dharavi has a population of between 600,000 and over 1 million people. Dharavi is one of the largest slums in the world. It used to be the largest slum in Mumbai at one time, but as of 2011, there are four slums in Mumbai larger than Dharavi.
In most large cities, the floor space index (FSI) varies from 5 to 15 in the Central Business District (CBD) to about 0.5, or below, in the suburbs. In Mumbai the permitted FSI is uniform and in 1991 was fixed at 1.33. The regulations that restrict the FSI greatly reduce the floor space available for residence and business. In expensive Mumbai, Dharavi provides a cheap alternative where rents were as low as US$4 per month in 2006. Dharavi exports goods around the world. The total (and largely informal) turnover is estimated to be between US$500 million and over US$650 million per year.
Dharavi is situated between Mumbai's two main suburban railway lines, the Western and Central Railways. To its west are Mahim and Bandra, and to the north lies the Mithi River, which empties into the Arabian Sea through the Mahim Creek. To its south and east are Sion and Matunga. Both its location and poor drainage systems make Dharavi particularly vulnerable to floods during the wet season.