Map - Indira Gandhi International Airport (Indira Gandhi International Airport)

Indira Gandhi International Airport is the primary international airport serving Delhi, the capital of India, and the National Capital Region (NCR). The airport, spread over an area of 5106 acres, is situated in Palam, Delhi, 15 km southwest of the New Delhi Railway Station and 16 km from New Delhi city centre. Named after Indira Gandhi (1917–1984), a former Prime Minister of India, it is the busiest airport of India in terms of passenger traffic since 2009. It is also the busiest airport in the country in terms of cargo traffic, overtaking Mumbai during late 2015. In the financial year of 2020, the airport handled 67.3 million passengers, the highest ever in the airport's history. As of 2022, it is the seventh busiest airport in the world, as per the latest rankings issued by the UK-based air consultancy firm, OAG. It is the second busiest airport in the world by seating capacity, having a seating capacity of over 3.6 million seats, and the busiest airport in Asia by passenger traffic, handling over 37 million passengers in 2021.

The airport was operated by the Indian Air Force before its management was transferred to the Airports Authority of India. In May 2006, the management of the airport was passed over to Delhi International Airport Limited (DIAL), a consortium led by the GMR Group. In September 2008, the airport inaugurated a 4430 m runway. With the commencement of operations at Terminal 3 in 2010, it became India's and South Asia's largest aviation hub. The Terminal 3 building has a capacity to handle 34 million passengers annually and was the world's 8th largest passenger terminal upon completion. The airport uses an advanced system called Airport Collaborative Decision Making (A-CDM) to help keep takeoffs and landings timely and predictable.

The other airport serving NCR is the Hindon Airport, which is much smaller in size and primarily handles regional flights out of the city under the UDAN Scheme. The former airport, which used to be the primary airport of NCR, Safdarjung Airport is now used mainly by VVIP helicopters and small charter helicopters due to its short runway. To stimulate the increasing traffic, a second airport, Noida International Airport is being constructed to offset the load of Indira Gandhi International Airport.

Safdarjung Airport was built in 1930 and was the main airport for Delhi until 1962. Due to increasing passenger traffic at Safdarjung, civilian operations were moved to Palam Airport (later renamed to IGIA) in 1962. Palam Airport had been built during World War II and after the British departed from India, it served as an Air Force Station for the Indian Air Force.

Palam Airport had a peak capacity of around 1,300 passengers per hour. In 1979–80, a total of 3 million domestic and international passengers flew into and out of Palam Airport. Owing to an increase in air traffic in the 70s and the 80's, an additional terminal with nearly four times the area of the old Palam terminal was constructed. With the inauguration of this new international terminal, Terminal 2, on 2 May 1986, the airport was renamed as Indira Gandhi International Airport (IGIA).

The old domestic airport (Palam) is known as Terminal 1 and was divided into separate buildings – 1A, 1B, and 1C. Blocks 1A and 1B were used to handle international operations while domestic operations took place in Block 1C. Block 1A and 1B later became dedicated terminals for domestic airlines and are currently closed down. It is planned that they will be demolished after the construction of newer terminals. Block 1C was also turned into a domestic arrivals terminal, and was rebuilt and opened on February 24, 2022. The newly constructed domestic departures block 1D is now used by all domestic low-cost airlines (IndiGo, and SpiceJet). There is also a separate technical area for VIP passengers. The domestic arrivals terminal 1C was demolished and rebuilt into a brand-new domestic arrivals terminal. For this expansion work, GoAir and select flights of IndiGo were moved to Terminal 2 as well as select flights of SpiceJet and IndiGo to Terminal 3.

The Delhi Airport gained a nonstop flight to North America in October 2001, when an Airbus A340 belonging to Canada 3000 touched down from Toronto. Even though the 11 September attacks had precipitated a global decline in air travel, Canada 3000 proceeded with launching the route, hoping it would help improve the airline's financial position. The opening of Russian airspace after the Cold War allowed pilots to fly over the Arctic, thereby reducing the flight duration. Nevertheless, Canada 3000 collapsed just one month after the service began.

Significant growth in the Indian aviation industry led to a major increase in passenger traffic. The capacity of Terminal 1 was estimated to be 7.15 million passengers per annum (mppa). The actual throughput for 2005/06 was an estimated 10.4 million passengers. Including the then closed down international terminal (Terminal 2), the airport had a total capacity of 12.5 million passengers per year, whereas the total passenger traffic in 2006/07 was 16.5 million passengers per year. In 2008, the total passenger count at the airport reached 23.97 million. To ease the traffic congestion on the existing terminals, a much larger Terminal 3 was constructed and inaugurated on 3 July 2010. The new terminal's construction took 37 months for completion and this terminal increased the airport's total passenger capacity by 34 million. Apart from the three budget domestic airlines handled by Terminals 1 and 2, all other airlines operate their flights from Terminal 3. On 1 June 2022, Delhi International Airport became India's first to run entirely on Hydro Power and solar energy. On 16 December 2022, IGI Airport installed 5 new x-ray machines at the security-check area, taking the total to 18 ATRS/x-ray machines.