Delhi, officially known as the National Capital Territory of Delhi (NCT), is a city and a union territory of India containing New Delhi, the capital of India. It is bordered by the state of Haryana on three sides and by Uttar Pradesh to the east. Delhi's urban area is now considered to extend beyond the NCT boundaries, and include the neighbouring satellite cities of Ghaziabad, Faridabad, Gurgaon and Noida in an area called the National Capital Region (NCR). Delhi is of great historical significance as an important commercial, transport, and cultural hub, as well as the political centre of India.
Source : Wikipedia