Mumbai is the capital city of the Indian state of Maharashtra. It is the most populous city in India and the ninth most populous agglomeration in the world, with an estimated city population of 18.4 million. Along with the neighbouring regions of the Mumbai Metropolitan Region, it is one of the most populous urban regions in the world and the seсond most populous metropolitan area in India, with a population of 20.7 million as of 2011. 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. Mumbai has the highest number of billionaires and millionaires among all cities in India.

The name Mumbai is derived from Mumbā or Mahā-Ambā—the name of the patron goddess (Kuladevi) Mumbadevi of the native Agri, Koli and Somvanshi Kshatriya communities and ā’ī meaning “mother” in the Marathi language, which is the mother tongue of the kolis and the official language of Maharashtra.

Mumbai is built on what was once an archipelago of seven islands: Bombay Island, Parel, Mazagaon, Mahim, Colaba, Worli, and Old Woman’s Island (also known as Little Colaba). It is not exactly known when these islands were first inhabited. Pleistocene sediments found along the coastal areas around Kandivali in northern Mumbai suggest that the islands were inhabited since the Stone Age. Perhaps at the beginning of the Common era (2,000 years ago), or possibly earlier, they came to be occupied by the Koli fishing community.

The Mughal Empire, founded in 1526, was the dominant power in the Indian subcontinent during the mid-16th century. Growing apprehensive of the power of the Mughal emperor Humayun, Sultan Bahadur Shah of the Gujarat Sultanate was obliged to sign the Treaty of Bassein with the Portuguese Empire on 23 December 1534. According to the treaty, the seven islands of Bombay, the nearby strategic town of Bassein and its dependencies were offered to the Portuguese. The territories were later surrendered on 25 October 1535.

After India’s independence in 1947, the territory of the Bombay Presidency retained by India was restructured into Bombay State. The area of Bombay State increased, after several erstwhile princely states that joined the Indian union were integrated into the state. Subsequently, the city became the capital of Bombay State.[108] On April 1950, Municipal limits of Bombay were expanded by merging the Bombay Suburban District and Bombay City to form the Greater Bombay Municipal Corporation.

Mumbai consists of two distinct regions: Mumbai City district and Mumbai Suburban district, which form two separate revenue districts of Maharashtra.The city district region is also commonly referred to as the Island City or South Mumbai. The total area of Mumbai is 603.4 km2 (233 sq mi). Of this, the island city spans 67.79 km2 (26 sq mi), while the suburban district spans 370 km2 (143 sq mi), together accounting for 437.71 km2 (169 sq mi) under the administration of Municipal Corporation of Greater Mumbai (MCGM). The remaining areas belong to various Defence establishments, the Mumbai Port Trust, the Atomic Energy Commission and the Borivali National Park, which are out of the jurisdiction of the MCGM.[132] The Mumbai Metropolitan Region which includes portions of Thane, Palghar and Raigad districts in addition to Greater Mumbai, covers an area of 4,355 km2 (1681.5 sq mi).

Mumbai is India’s largest city (by population) and is the financial and commercial capital of the country as it generates 6.16% of the total GDP. It serves as an economic hub of India, contributing 10% of factory employment, 25% of industrial output, 33% of income tax collections, 60% of customs duty collections, 20% of central excise tax collections, 40% of India’s foreign trade and ₹4,000 crore (US$590 million) in corporate taxes.Along with the rest of India, Mumbai has witnessed an economic boom since the liberalisation of 1991, the finance boom in the mid-nineties and the IT, export, services and outsourcing boom in 2000s.Although Mumbai had prominently figured as the hub of economic activity of India in the 1990s, the Mumbai Metropolitan Region is presently witnessing a reduction in its contribution to India’s GDP.

Mumbai’s culture is a blend of traditional festivals, food, music, and theatres. The city offers a cosmopolitan and diverse lifestyle with a variety of food, entertainment, and night life, available in a form and abundance comparable to that in other world capitals. Mumbai’s history as a major trading centre has led to a diverse range of cultures, religions, and cuisines coexisting in the city. This unique blend of cultures is due to the migration of people from all over India since the British period.