At least five people died of suspected heat stroke in India's southern city of Chennai on Sunday at an Indian Air Force show that was attended by about 1.5 million people, officials said on Monday.

The air show to celebrate the air force's 92nd anniversary was organised at the iconic Marina Beach — among the world's longest beaches — on a day when the maximum temperature touched 35°C (95°F), according to the weather department.

Chandramohan, a software engineer who attended the event and uses only one name, said there was no water supply at the function despite the "hot and humid" weather and he saw people fainting due to the heat and dehydration.

"Worst was the exit after the event. Roads were choked...Buses got stuck too," he said.

M K Stalin, the chief minister of Tamil Nadu state of which Chennai is the capital, attributed the deaths to "extreme heat and various medical reasons" and said that although coordination had been done to avoid crowding, the number of people who turned up was "much higher than expected".

"Next time such big events are organised, more attention and arrangements will be made," he said in a statement.

Ma Subramanian, state minister for medical and family welfare, said in a post on X that the government had provided medical teams, security, temporary toilets, and drinking water supply for the event.

Officials from the air force did not immediately respond to a request for comment.