Map - Mumbai

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 20 million (2 crore). As per the Indian government population census of 2011, Mumbai was the most populous city in India, with an estimated city proper population of 12.5 million (1.25 crore) 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 23 million (2.3 crore). 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.

The seven islands that constitute Mumbai were earlier home to communities of Marathi language speaking Koli people. For centuries, the seven islands of Bombay were under the control of successive indigenous rulers before being ceded to the Portuguese Empire, and subsequently to the East India Company in 1661, through the dowry of Catherine Braganza when she was married off to Charles II of England. During the mid-18th century, Bombay was reshaped by the Hornby Vellard project, which undertook reclamation of the area between the seven islands from the sea. Along with construction of major roads and railways, the reclamation project, completed in 1845, transformed Bombay into a major seaport on the Arabian Sea. Bombay in the 19th century was characterised by economic and educational development. During the early 20th century it became a strong base for the Indian independence movement. Upon India's independence 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 the capital.

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. 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.

The name Mumbai (Marathi: मुंबई, Gujarati: મુંબઈ, Hindi: मुंबई) derived from Mumbā or Mahā-Ambā—the name of the patron goddess (kuladevata) Mumbadevi of the native Koli community —and ā'ī meaning "mother" in the Marathi language, which is the mother tongue of the Koli people and the official language of Maharashtra. The Koli people originated in Kathiawar and Central Gujarat, and according to some sources they brought their goddess Mumba with them from Kathiawar (Gujarat), where she is still worshipped. However, other sources disagree that Mumbai's name was derived from the goddess Mumba.

The oldest known names for the city are Kakamuchee and Galajunkja; these are sometimes still used. In 1508, Portuguese writer Gaspar Correia used the name "Bombaim" in his Lendas da Índia (Legends of India). This name possibly originated as the Galician-Portuguese phrase bom baim, meaning "good little bay", and Bombaim is still commonly used in Portuguese. In 1516, Portuguese explorer Duarte Barbosa used the name Tana-Maiambu: Tana appears to refer to the adjoining town of Thane and Maiambu to Mumbadevi.

Other variations recorded in the 16th and the 17th centuries include: Mombayn (1525), Bombay (1538), Bombain (1552), Bombaym (1552), Monbaym (1554), Mombaim (1563), Mombaym (1644), Bambaye (1666), Bombaiim (1666), Bombeye (1676), Boon Bay (1690), and Bon Bahia. After the English gained possession of the city in the 17th century, the Portuguese name was anglicised as Bombay. Ali Muhammad Khan, imperial dewan or revenue minister of the Gujarat province, in the Mirat-i Ahmedi (1762) referred to the city as Manbai.

The French traveller Louis Rousselet, who visited in 1863 and 1868, states in his book L'Inde des Rajahs, which was first published in 1877: "Etymologists have wrongly derived this name from the Portuguese Bôa Bahia, or (French: "bonne bai", English: "good bay"), not knowing that the tutelar goddess of this island has been, from remote antiquity, Bomba, or Mumba Devi, and that she still ... possesses a temple".

By the late 20th century, the city was referred to as Mumbai or Mambai in Marathi, Konkani, Gujarati, Kannada and Sindhi, and as Bambai in Hindi. The Government of India officially changed the English name to Mumbai in November 1995. This came at the insistence of the Marathi nationalist Shiv Sena party, which had just won the Maharashtra state elections, and mirrored similar name changes across the country and particularly in Maharashtra. According to Slate magazine, "they argued that 'Bombay' was a corrupted English version of 'Mumbai' and an unwanted legacy of British colonial rule." Slate also said "The push to rename Bombay was part of a larger movement to strengthen Marathi identity in the Maharashtra region." While the city is still referred to as Bombay by some of its residents and by some Indians from other regions, mention of the city by a name other than Mumbai has been controversial, resulting in emotional outbursts, sometimes of a violently political nature.