Mumbai /mʊmˈbaɪ/, also known as Bombay, is the capital city of the Indian state of Maharashtra. It is the most populous city in India, and the fourth most populous city in the world, with a total metropolitan area population of approximately 20.5 million. Along with the neighbouring urban areas, including the cities of Navi Mumbai and Thane, it is one of the most populous urban regions in the world. Mumbai lies on the west coast of India and has a deep natural harbour. In 2009, Mumbai was named an Alpha world city. It is also the wealthiest city in India, and has the highest GDP of any city in South, West or Central Asia.
The seven islands that came to constitute Mumbai were home to communities of fishing colonies. For centuries, the islands were under the control of successive indigenous empires before being ceded to the Portuguese and subsequently to the British East India Company. During the mid-18th century, Mumbai was reshaped by the Hornby Vellard project, which undertook the reclamation of the area between the seven constituent islands from the sea. Completed by 1845, the project along with construction of major roads and railways transformed Bombay into a major seaport on the Arabian Sea. Economic and educational development characterised the city during the 19th century. It became a strong base for the Indian independence movement during the early 20th century. When India became independent in 1947, the city was incorporated into Bombay State. In 1960, following the Samyukta Maharashtra movement, a new state of Maharashtra was created with Bombay as capital. The city was renamed Mumbai in 1996, the name being derived from the Koli goddess—Mumbadevi.
Mumbai is the commercial and entertainment capital of India, it is also one of the world's top 10 centres of commerce in terms of global financial flow, generating 5% of India's GDP, and accounting for 25% of industrial output, 70% of maritime trade in India (Mumbai Port Trust & JNPT), and 70% of capital transactions to India's economy. The city houses important financial institutions such as the Reserve Bank of India, the Bombay Stock Exchange, the National Stock Exchange of India, the SEBI and the corporate headquarters of numerous Indian companies and multinational corporations. It is also home to some of India's premier scientific and nuclear institutes like BARC, NPCL, IREL, TIFR, AERB, AECI, and the Department of Atomic Energy. The city also houses India's Hindi (Bollywood) and Marathi film and television industry. Mumbai's business opportunities, as well as its potential to offer a higher standard of living, attract migrants from all over India and, in turn, make the city a melting pot of many communities and cultures.