[20] The topography of the medieval fort Purana Qila on the banks of the river Yamuna matches the literary description of the citadel Indraprastha in the Sanskrit epic Mahabharata; however, excavations in the area have revealed no signs of an ancient built environment.

During the Partition of India in 1947, Delhi was transformed from a Mughal city to a Punjabi one, losing two-thirds of its Muslim residents, in part due to the pressure brought to bear by arriving Hindu and Sikh refugees from western Punjab.

Delhi ranks fifth among the Indian states and union territories in human development index,[22] and has the second-highest GDP per capita in India (after Goa).

The earliest, Indraprastha, is part of a literary description in the Sanskrit epic Mahabharata (composed c. 400 BCE to 300 CE but describing an earlier time[38]) which situates a city on a knoll on the banks of the river Yamuna.

According to art historian Catherine B. Asher, the topographical description of the Mahabharata matches the area of Purana Qila, a 14th-century CE fort of the Delhi sultanate, but the analogy does not go much further.

Under the Afghan Lodi dynasty (1451–1526), the sultanate recovered control of Punjab and the Gangetic plain to once again achieve domination over Northern India.

[citation needed] In 1526, Babur, a descendant of Genghis Khan and Timur from the Fergana Valley in modern-day Uzbekistan, invaded India and defeated the last Lodhi sultan in the First Battle of Panipat and founded the Mughal Empire that ruled from Delhi and Agra.

In 1739, the Mughal Empire lost the huge Battle of Karnal in less than three hours against the numerically outnumbered but militarily superior Persian army led by Nader Shah of Persia.

After his invasion, he completely sacked and looted Delhi, carrying away immense wealth including the Peacock Throne, the Daria-i-Noor, and Koh-i-Noor.

The Mughals, severely further weakened, could never overcome this crushing defeat and humiliation which also left the way open for more invaders to come, including eventually the British.

[76] Existing policy in Delhi prevents the conversion of wetlands and, quite inadvertently, has led to the city's ponds becoming invaluable refugia for birds.

[108][109][110] During 2013–14, peak levels of fine particulate matter (PM) increased by about 44%, primarily due to high vehicular and industrial emissions, construction work and crop burning in adjoining states.

[114] Rising air pollution level has significantly increased lung-related ailments (especially asthma and lung cancer) among Delhi's children and women.

[118] India's Ministry of Earth Sciences published a research paper in October 2018 attributing almost 41% of PM2.5 air pollution in Delhi to vehicular emissions, 21.5% to dust/fire and 18% to industries.

[104] In 2014, an environmental panel appealed to India's Supreme Court to impose a 30% cess on diesel cars, but till date no action has been taken to penalise the automobile industry.

[125] In 1996, the CSE started a public interest litigation in the Supreme Court of India that ordered the conversion of Delhi's fleet of buses and taxis to run on CNG and banned the use of leaded petrol in 1998.

In 2003, Delhi won the United States Department of Energy's first 'Clean Cities International Partner of the Year' award for its "bold efforts to curb air pollution and support alternative fuel initiatives".

[126] However, according to several authors, most of these gains have been lost, especially due to stubble burning, a rise in the market share of diesel cars and a considerable decline in bus ridership.

[127][128] According to CSE and System of Air Quality Weather Forecasting and Research (SAFAR), burning of agricultural waste in nearby Punjab, Haryana and Uttar Pradesh regions results in severe intensification of smog over Delhi.

[163] The state-owned MTNL and private enterprises such as Airtel, Vi, Jio, and provide telephone and cell phone services to the city.

Since then, the club only carries out aircraft maintenance courses and is used for helicopter rides to Indira Gandhi International Airport for VIP including the president and the prime minister.

In 1998, the Supreme Court of India ruled that all public transport vehicles in Delhi must be fuelled by compressed natural gas (CNG) to tackle increasing vehicular pollution.

[180] The state-owned Delhi Transport Corporation (DTC) is a major bus service provider which operates the world's largest fleet of CNG-fuelled buses.

[181][182] In addition, cluster scheme buses are operated by Delhi Integrated Multi-Modal Transit System (DIMTS) with the participation of private concessionaires and DTC.

To meet the transport demand, the State and Union government constructed a mass rapid transit system, including the Delhi Metro.

Although a strong Punjabi Influence can be seen in language, dress and cuisine brought by the large number of refugees who came following the partition in 1947 the recent migration from other parts of India has made it a melting pot.

[218] In the Old City, the Mughals and the Turkic rulers constructed several architecturally significant buildings, such as the Jama Masjid—India's largest mosque[219] built in 1656[220] and the Red Fort.

New Delhi houses several government buildings and official residences reminiscent of British colonial architecture, including the Rashtrapati Bhavan, the Secretariat, Rajpath, the Parliament of India and Vijay Chowk.

[252] Other major English newspapers include The Times of India, The Hindu, The Indian Express, Business Standard, The Pioneer, The Statesman, and The Asian Age.

[268] It has produced several world-class international cricketers such as Virender Sehwag, Virat Kohli,[269] Gautam Gambhir, Madan Lal, Chetan Chauhan, Shikhar Dhawan, Ishant Sharma, Manoj Prabhakar and Bishan Singh Bedi to name a few.