New Delhi, Nov. 14: More than a hundred rescuers in northern India on Tuesday struggled for a third day to save workers trapped underground after the road tunnel they were building collapsed.

Excavators have been removing debris since Sunday morning from the site in the Himalayan state of Uttarakhand to create an escape tunnel for the 40 workers, who are all alive.

"Our biggest breakthrough is that we have established contact and there is a supply of oxygen and food," Uttarkashi district's top civil servant Abhishek Ruhela told AFP on Tuesday.

"Whatever is necessary for their survival is being done.Oxygen was being pumped into the tunnel and small food items like dry fruit were being provided to the workers,” he added.

Photographs released by government rescue teams soon after the collapse showed huge piles of rubble blocking the wide tunnel, with twisted metal bars from its roof poking down in front of slabs of concrete.

Teams are using heavy machinery to drive a steel pipe with a width of 90 centimetres (nearly three feet), wide enough for the trapped men to squeeze through the rubble, the government's highway and infrastructure company said.

The 4.5-kilometre (2.7-mile) tunnel is being constructed between the towns of Silkyara and Dandalgaon to connect two of the holiest Hindu shrines: Uttarkashi and Yamunotri.

The tunnel is part of a Prime Minister Narendra Modi road project aimed at improving travel conditions between some of the most popular Hindu shrines in the country as well as areas bordering China.

Accidents on large infrastructure projects 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.-Agencies