Delhi (/ˈdɛli/, Hindustani pronunciation: [d̪ɪlliː]Dilli; Devanāgarī: दिल्ली), officially the National Capital Territory of Delhi (NCT), is a city and a union territory of India. It is bordered by Haryana on three sides and by Uttar Pradesh to the east. It is the most expansive city in India—about 1,484 square kilometres (573 sq mi). It has a population of about 25 million, making it the second most populous city after Mumbai and most populous urban agglomeration in India and 3rd largest urban area in the world. Urban expansion in Delhi has caused it to grow beyond the NCT to incorporate towns in neighbouring states. At its largest extent, there is a population of about 25 million residents as of 2014. After Mumbai, Delhi has the second-highest number of billionaires and millionaires in India.
Delhi has been continuously inhabited since the 6th century BCE. Through most of its history, Delhi has served as a capital of various kingdoms and empires. It has been captured, ransacked and rebuilt several times, particularly during the medieval period, and modern Delhi is a cluster of a number of cities spread across the metropolitan region.
Delhi and its urban region have been given the special status of National Capital Region (NCR) under the Constitution of India's 69th Amendment Act of 1991. The NCR includes the neighbouring cities of Faridabad, Gurgaon, Noida, Ghaziabad, Greater Faridabad, Greater Noida, Bahadurgarh, Sonepat, Panipat, Karnal, Rohtak, Bhiwani, Rewari, Baghpat, Meerut, Muzaffarnagar, Alwar, Bharatpur and other nearby towns. A union territory, the political administration of the NCT of Delhi today more closely resembles that of a state of India, with its own legislature, high court and an executive council of ministers headed by a Chief Minister. New Delhi is jointly administered by the federal government of India and the local government of Delhi, and is the capital of the NCT of Delhi. Delhi hosted the first and ninth Asian Games in 1951 and 1982 respectively, 1983 NAM Summit, 2010 Men's Hockey World Cup, 2010 Commonwealth Games, 2012 BRICS Summit and was one of the major host cities of the 2011 Cricket World Cup.