Kolkata is the capital of the Indian state of West Bengal. Located on the east bank of the Hooghly river, it is the principal commercial, cultural, and educational centre of East India, while the Port of Kolkata is India's oldest operating port as well as its sole major riverine port. As of 2011, the city had 4.5 million residents; the urban agglomeration, which comprises the city and its suburbs, was home to approximately 14.1 million, making it the third-most populous metropolitan area in India. As of 2008, its economic output as measured by gross domestic product ranked third among South Asian cities, behind Mumbai and Delhi. As a growing metropolitan city in a developing country, Kolkata confronts substantial urban pollution, traffic congestion, poverty, overpopulation, and other logistic and socioeconomic problems.
Kolkata is the main commercial and financial hub of East and North-East India and home to the Calcutta Stock Exchange. It is a major commercial and military port, and is the only city in eastern India to have an international airport. Once India's leading city, Kolkata experienced a steady economic decline in the decades following India's independence due to steep population increases and a rise in militant trade-unionism, which included frequent strikes that were backed by left-wing parties.
Kolkata is known for its literary, artistic, and revolutionary heritage; as the former capital of India, it was the birthplace of modern Indian literary and artistic thought. Kolkata has been called the "City of Furious, Creative Energy" as well as the "cultural or literary capital of India". The presence of paras, which are neighbourhoods that possess a strong sense of community, is characteristic of Kolkata. Typically, each para has its own community club and, on occasion, a playing field. Residents engage in addas, or leisurely chats, that often take the form of freestyle intellectual conversation. The city has a tradition of political graffiti depicting everything from outrageous slander to witty banter and limericks, caricatures, and propaganda.
The most popular sports in Kolkata are football and cricket. The city is a centre of football activity in India and is home to top national clubs such as Mohun Bagan A.C., Kingfisher East Bengal F.C., Prayag United S.C., and the Mohammedan Sporting Club. Calcutta Football League, which was started in 1898, is the oldest football league in Asia. Mohun Bagan A.C., one of the oldest football clubs in Asia, is the only organisation to be dubbed a "National Club of India".
As in the rest of India, cricket is popular in Kolkata and is played on grounds and in streets throughout the city. Kolkata has an Indian Premier League franchise known as the Kolkata Knight Riders; the Cricket Association of Bengal, which regulates cricket in West Bengal, is also based in the city. Tournaments, especially those involving cricket, football, badminton, and carrom, are regularly organised on an inter-locality or inter-club basis. The Maidan, a vast field that serves as the city's largest park, hosts several minor football and cricket clubs and coaching institutes.