Delhi, locally pronounced as Dilli officially National Capital Territory of Delhi (NCT), is the largest metropolis by area and the second-largest metropolis by population in India.
There are nearly 22.2 million residents in the greater National Capital Region urban area (which also includes Noida, Greater Noida, Ghaziabad, Gurgaon and Faridabad along with other smaller nearby towns).
Located on the banks of the River Yamuna, Delhi has been known to be continuously inhabited since at least the 6th century BCE.
Web : http://en.wikipedia.org/wiki/Delhi