SILKYARA (India), Nov 25 ― Efforts to rescue 41 workers trapped in a highway tunnel in the Indian Himalayas for two weeks will be further slowed as rescuers are considering drilling through the last 10 metres of debris manually, an official said today.

The heavy drill machine being used to break through the nearly 60 metres of debris was damaged on Friday and needs to be pulled out entirely, according to an official statement.

The men, construction workers from some of India's poorest states, have been stuck in the 4.5-km (3-mile) tunnel being built in Uttarakhand state since it caved in early on November 12. Authorities have said they are safe, with access to light, oxygen, food, water and medicines.

A senior official involved in the rescue mission told Reuters that since the damaged machine cannot be used, they are planning to cut through the remaining debris manually.

The drill machine, called an auger, was damaged as it was being pulled out of the nearly 47-metre pipe inserted to bring out the trapped workers, after hitting an obstacle yesterday.

The machine broke at a joint and some parts are being cut so it can be pulled from the tunnel. Once it has been removed, drilling will be done manually, the official said.

Sunita Hembrom, who spoke to her trapped brother-in-law Birendra Kishku, 39, said that "everyone trapped inside is very worried”.

"My brother-in-law told me that he has hasn't eaten any food since yesterday. We are very worried,” she said.

Authorities have not said what caused the tunnel collapse, but the region is prone to landslides, earthquakes and floods.

The tunnel did not have an emergency exit and was built through a geological fault, a member of a panel of experts investigating the disaster said yesterday on condition of anonymity as they are not authorised to speak to media.

The rescue plan involves pushing a pipe wide enough to pull the trapped men out on wheeled stretchers. Rescue workers rehearsed the evacuation by going into the pipe and being pulled out on stretchers, a video clip provided by the authorities showed.

A second plan to drill vertically from atop the hill is also being pursued and the drilling machines are being assembled, the statement said.

The men have been getting cooked food since a larger lifeline pipe was pushed through earlier this week and the statement said they were sent 200 rotis or Indian round flat bread, lentils and vegetable curry.

More than a dozen doctors, including psychiatrists, have been at the site, talking to the men and monitoring their health.

They have been advised to do light yoga exercises, walk around in the 2-km space they have been confined to, and to keep speaking to each other. Rohit Gondwal, a psychiatrist, said they were also considering sending in playing cards and board games.

The collapsed tunnel is on the Char Dham pilgrimage route, one of the most ambitious projects of Prime Minister Narendra Modi's government.

It aims to link four key Hindu pilgrimage sites with 890km (550 miles) of two-lane road, at a cost of US$1.5 billion (RM7 billion). ― Reuters