Rescue workers in northern India said on Monday they had made contact with 40 workers trapped for over 24 hours after the road tunnel they were building collapsed.

“All the 40 workers trapped inside the tunnel are safe,” Karamveer Singh Bhandari, a senior commander in the National Disaster Response Force told AFP, from the site in the Himalayan state of Uttarakhand.

“We sent them water and food,” Bhandari said.

The collapse occurred early on Sunday morning, with rescue teams using heavy excavators to clear piles of debris in desperate efforts to reach the 40 men.

Oxygen was being pumped into the blocked portion of the tunnel, with food sent through a water pipe. Initial contact was made via a note on a scrap of paper, but later rescuers managed to connect using radio handsets.

“Some small food packets were sent in through a pipe which is also taking oxygen inside,” rescue official Durgesh Rathodi told AFP from the site.

Rathodi said excavators had removed about 20 metres of heavy debris, but the men were 40 metres beyond that point.

“Due to excess debris in the tunnel, we are facing some difficulty in the rescue, but our team is leaving no stone unturned,” Bhandari added.

‘Bring them out safely’

Uttarakhand chief minister Pushkar Singh Dhami, who on Monday flew to the site of the accident, said the work to remove the tons of tumbled concrete debris was “being made continuously to bring them out safely”, he wrote on social media platform X, formerly Twitter.

“Contact has been made with the workers trapped in the tunnel through a walkie-talkie,” he said.

“Efforts are being made to get them out safely soon,” he added.

One rescue worker, quoted by the Press Trust of India news agency, said the men were contacted shortly after midnight on Monday.

Disaster response official Devendra Patwal said that while the men were trapped, they had space in the tunnel area where they were.

“The good thing is that the labourers are not crammed in, and have a buffer of around 400 metres to walk and breathe,” Patwal told the Indian Express newspaper.

The 4.5 kilometre tunnel is being constructed between Silkyara and Dandalgaon to connect two of the holiest Hindu shrines of Uttarkashi and Yamunotri.

Photographs released by the government rescue teams showed huge piles of rubble blocking the wide tunnel, with twisted metal bars on its broken roof poking down in front of the rubble.

The tunnel is part of Prime Minister Narendra Modi’s Char Dham Road Project, which is meant to improve connectivity for some of the most popular Hindu shrines in the country, as well as areas bordering China.

Accidents on large infrastructure construction sites are common in India.

In January, at least 200 people were killed in flash floods in ecologically fragile Uttarakhand in a disaster that experts partly blamed on excessive development.