Delhi (Hindi: दिल्ली; Punjabi: ਦਿੱਲੀ; Urdu: دلی; IPA: [d̪ɪlːiː]; sometimes referred to as Dilli) is the second largest metropolis in India, with a population of 17 million [4], and a federally-administered union territory officially known as the National Capital Territory of Delhi (NCT). Located on the banks of the Yamuna River in northern India, it is one of the oldest continually inhabited cities in the world.

Delhi has been the capital of several ancient Indian empires and a major city along the old trade routes between northwest India and the Indo-Gangetic Plains. It is the site of many ancient and medieval monuments, archaeological sites and remains. The Mughal emperor Shahjahan built the city, now known as "Old Delhi", to serve as the capital of the Mughal Empire from 1649 to 1857.

After the British Raj took control of India during the 19th century, Calcutta became the capital until George V announced in 1911 that it was to move back to Delhi. A new capital city, New Delhi, was built during the 1920s. When India gained independence from British rule in 1947, New Delhi was declared its capital and seat of government. As such, New Delhi houses important offices of the federal government, including the Parliament of India.

Owing to the immigration of people from across the country, Delhi has grown to be a cosmopolitan city. Its rapid development and urbanisation, coupled with the relatively high average income of its population, has transformed the city.[5] Today, Delhi is a major cultural, political, and commercial center of India.