A Brief Overview of Delhi Delhi , officially the National Capital Territory of Delhi (NCT), is a city and a union territory of India. According to the 2011 census, Delhi city's proper population was over 11 million, the second-highest in India after Mumbai, while the whole NCT's population was about 16.8 million. A seat of many powerful empires in the past, Delhi's long history can be traced in its many carefully-preserved monuments, ancient forts and tombs. Through most of i