'''Delhi''' (;  ''Dillī'';  ''Dillī'';  ''Dêhlī''), officially the '''National Capital Territory''' ('''NCT''') '''of Delhi''', is a city and a union territory of India containing New Delhi, the capital of India. Located on the Yamuna river, Delhi is bordered by the state of Haryana on three sides and by Uttar Pradesh to the east. The NCT covers an area of . According to the 2011 census, Delhi's city proper population was over 11 million, while the NCT's population was about 16.8 million. Delhi's urban agglomeration, which includes the satellite cities of Ghaziabad, Faridabad, Gurgaon and Noida in an area known as the National Capital Region (NCR), has an estimated population of over 28 million, making it the largest metropolitan area in India and the second-largest in the world (after Tokyo). Recent estimates of the metropolitan economy of its urban area have ranked Delhi either the most or second-most productive city of India. Delhi is the second-wealthiest city in India (after Mumbai), and is home to 18 billionaires and 23,000 millionaires. Delhi ranks fifth among the Indian states and union territories in human development index. Delhi has the second-highest GDP per capita in India (after Goa). Delhi is of great historical significance as an important commercial, transport, and cultural hub, as well as the political centre of India.——