Mumbai, formerly known as Bombay, is the capital of the state of Maharashtra and the most populous city of India. By some measures, it is also the most populous city in the world with an estimated population of about 13 million (or about 20 million if you include some of the outlying suburbs). The city is built on on Salsette Island, off the west coast of Maharashtra. The city has a deep natural harbour and the port handles over half of India's passenger traffic and a significant amount of cargo.
Mumbai is the commercial and entertainment capital of India, and houses important financial institutions, such as the Reserve Bank of India (RBI), the Bombay Stock Exchange (BSE), the National Stock Exchange of India (NSE) and the corporate headquarters of many Indian companies. Mumbai has attracted migrants from all over India because of the immense business opportunities, and the relatively high standard of living, making the city a potpourri of various communities and cultures. The city is home to India's Hindi film and television industry, known as Bollywood. Mumbai is also one of the rare cities to accommodate a national park, the Sanjay Gandhi National Park, within its city limits.