Delhi, known locally as Dilli (Hindi: दिल्ली, Punjabi: ਦਿੱਲੀ, Urdu: دلّی dillī), and also by the official name National Capital Territory of Delhi (NCT), is the largest metropolis by area and the second-largest metropolis by population in India. It is the eighth largest metropolis in the world by population with more than 12.25 million inhabitants in the territory and with over 15.9 million residents in the National Capital Region region (which also includes Noida, Gurgaon, Faridabad and Ghaziabad). The name Delhi is often also used to include some urban areas near the NCT, as well as to refer to New Delhi, the capital of India, which lies within the NCT. The NCT is a federally administered union territory.

New Delhi (Hindi: नई दिल्ली, Punjabi: ਨਵੀਂ ਦਿੱਲੀ, Urdu: نئی دلی) is the capital city of India. With a total area of 42.7 km2, New Delhi is situated within the metropolis of Delhi and serves as the seat of the Government of India and the Government of the National Capital Territory of Delhi (NCT).

Planned by Edwin Lutyens, a leading 20th century British architect, New Delhi is known for its wide, tree-lined boulevards and houses numerous national institutions and landmarks.