Rawat, 63, was travelling with his wife and other senior officers when their aircraft crashed in a forest in southern Tamil Nadu state, killing all but one soldier on board.

His body arrived in the capital for Friday's funeral after a solemn ceremony near the accident site at an army base, where an honour guard laid wreaths by the coffins of the victims.

"The last rites of the Chief of Defence Staff will be performed with full military honours," defence minister Rajnath Singh told parliament.

Rawat was India's first chief of defence staff, a position that the government established in 2019, and was seen as close to Prime Minister Narendra Modi.

He was an outspoken and polarising but hugely popular officer who came from a military family and had already survived a helicopter accident in 2015, with minor injuries.

The general was headed to the Defence Services Staff College to address students and faculty on Wednesday when the Mi-17 chopper crashed in foggy conditions.

India's air force is investigating what caused the accident.

"We rescued as many people as we could. But it was very difficult," said Sahayaraj, an eyewitness to the crash. "The whole area was on fire and we couldn't go too close to it."

Captain Varun Singh, the sole survivor of the crash, remained in a critical condition and had been flown to Bangalore to continue his treatment at a military hospital, local media reported.