Mumbai is the capital city of the Indian state of Maharashtra and the largest metropolis in the country. A population of around 20 million people makes Mumbai the second-most populated metropolis in India after Delhi, and the world's seventh-most populous city by population according to the United Nations. With an estimated city-proper population of 12.5 million people residing under the jurisdiction of the Municipal Corporation of Greater Mumbai, Mumbai was the most populated city in India in 2011, according to a population census conducted by the Indian government. There are about 23 million people living in the Mumbai Metropolitan Region, which is the sixth most populated metropolitan region in the world. Mumbai is the administrative centre of the Mumbai Metropolitan Region. A deep natural harbour serves Mumbai, which is located along India's Konkan coast on the country's west coast. Mumbai was designated as a "Alpha World City" in 2008. It is the city with the largest concentration of millionaires and billionaires among all Indian cities. The Elephanta Caves, the Chhatrapati Shivaji Maharaj Terminus, and the city's unique ensemble of Victorian and Art Deco structures are all designated as UNESCO World Heritage Sites.
The seven islands that make up the city of Mumbai were originally inhabited by groups of Koli people who spoke the Marathi language. Before being transferred by successive indigenous kings to the Portuguese Empire and then to the East India Company in 1661, when Catherine Braganza was married off to Charles II of England, the seven islands of Bombay had been under the jurisdiction of various indigenous rulers for generations. The Hornby Vellard project, which began in the mid-18th century and included the reclamation of the territory between the seven islands from the sea, had a significant impact on the development of Bombay. Bombay was turned into a major seaport on the Arabian Sea as a result of the reclamation project, which was finished in 1845 and coincided with the development of important roads and railroads. The growth of Bombay's economy and educational system throughout the nineteenth century was notable. During the early twentieth century, it became into a powerful foundation for the Indian independence movement, which was based there. When India gained its independence in 1947, the city was integrated into the newly formed state of Bombay. As a result of the Samyukta Maharashtra Movement, the state of Maharashtra was established in 1960, with Bombay serving as its capital.
Mumbai is India's financial, commercial, and entertainment capital, as well as its financial, commercial, and entertainment capital. Furthermore, it is one of the world's top ten commerce hubs in terms of global financial flow, contributing 6.16 percent to India's GDP and accounting for 25 percent of industrial output, 70 percent of maritime trade in India (through the Mumbai Port Trust and the Joint National Ports Authority), and 70 percent of capital transactions to the Indian economy. Mumbai has the eighth-largest 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 is home to key financial institutions as well as the corporate headquarters of a large number of Indian enterprises as well as foreign organisations. It is also the location of some of India's most prestigious scientific and nuclear research institutions. In addition, the city is home to the Bollywood and Marathi film industries. The business prospects in Mumbai draw people from all around India to the city.