Mumbai also known as Bombay (the official name until 1995) is the capital city of the Indian state of Maharashtra and the de facto financial centre of India. According to the United Nations, as of 2018, Mumbai is the second-most populous city in India after Delhi and the eighth-most populous city in the world with a population of roughly 2 crore (20 million).
As per the Indian government population census of 2011, Mumbai was the most populous city in India with an estimated city proper population of 1.25 crore (12.5 million) living under the Brihanmumbai Municipal Corporation. Mumbai is the centre of the Mumbai Metropolitan Region, the sixth most populous metropolitan area in the world with a population of over 2.3 crore (23 million). Mumbai lies on the Konkan coast on the west coast of India and has a deep natural harbour. In 2008, Mumbai was named an alpha world city. It has the highest number of millionaires and billionaires among all cities in India. Mumbai is home to three UNESCO World Heritage Sites: the Elephanta Caves, Chhatrapati Shivaji Maharaj Terminus, and the city's distinctive ensemble of Victorian and Art Deco buildings designed in the 19th and 20th centuries.
Mumbai is the financial, commercial, and the entertainment capital of India. It is also one of the world's top ten centres of commerce in terms of global financial flow, generating 6.16% of India's GDP, and accounting for 25% of industrial output, 70% of maritime trade in India (Mumbai Port Trust and JNPT), and 70% of capital transactions to India's economy.
Mumbai has the eighth-highest number of billionaires of any city in the world, and Mumbai's billionaires had the highest average wealth of any city in the world in 2008.The city houses important financial institutions 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. The city is also home to Bollywood and Marathi cinema industries. Mumbai's business opportunities attract migrants from all over India.