Heavy rainfall and winds brought down a roof at the main airport in New Delhi on Friday, killing one person and disrupting flights from a domestic terminal, while flooded streets and traffic snarls threw daily life out of gear in India's capital.

The airport area received about 148.5mm of rain over three hours in the early morning, more than the average for all of June, according to India's weather office.

The city of 20 million people received 228.1mm rainfall at its main Safdarjung weather station in the 24 hours ending 8.30am local time on Friday, a 266 percent departure from normal.

A portion of the canopy at the departure area of Terminal 1 collapsed and flight operations were shut down until 2pm, India's aviation minister told reporters.

The entire terminal, one of three at the country's biggest and busiest airport, was evacuated and an inquiry ordered into the collapse, said the minister, Kinjarapu Rammohan Naidu.

Rescue work had been completed and eight injured people were taken to hospital, said Atul Garg, the director of Delhi Fire Service.

At least 10 flights were cancelled and 40 were delayed while departures from Delhi airport were running late by an average of 50 minutes, according to data from flight tracking platform Flightradar24.

Arrivals and departures of flights scheduled from Terminal 1 after 2pm were diverted through the other two terminuses, Naidu said, adding that passengers will receive full refunds or have the option of booking on alternate flights and routes.

Visuals from Indian TV channels showed a taxi crushed under a wrecked metal pillar at the entrance area of the terminal, which is mostly used by low-cost carriers IndiGo, operated by Interglobe Aviation, and SpiceJet for domestic flights.

Around 10-12 cars were damaged and vehicles were still being pulled out from under the debris, said one of the workers at the airport.

"I first missed my flight in the morning due to floods. Then my 2.10pm Indigo flight to Bangalore has been cancelled. I have to urgently reach Bangalore for an official meeting," said Asif Ali, a businessman standing outside Terminal 1.

Many other parts of Delhi were flooded as well and cars trapped in thigh-deep water.

Metro services were affected, traffic snarls were reported from several parts of the city while several residents also complained of power cuts.

Ahead of the April-May general election, Prime Minister Narendra Modi inaugurated or laid the foundation stone of new terminal buildings at 15 airports at a cost of 98 billion rupees (US$1.17 billion).

Both Delhi's Terminal 1 and the terminal at Jabalpur were part of the projects.

Opposition parties criticised Modi's government, saying projects were inaugurated in a hurry before the election.

"Corruption and criminal negligence is responsible for the collapse of shoddy infrastructure falling like a deck of cards, in the past 10 years of Modi Govt," Mallikarjun Kharge, the president of the main opposition Congress party, said on X.

Aviation Minister Naidu defended the government, saying the roof collapse at Delhi's airport was part of an old building that was opened in 2009 and not the one Modi inaugurated in March. (Reuters)