The lives of 40 Indian labourers, who have been trapped in a tunnel for more than 72 hours, hang in the balance as authorities try to rescue them.
The workers were building the tunnel in northern Uttarakhand state when a part of it caved in due to a landslide on Sunday.
State and federal rescue teams have been using a massive drill to push through the debris to reach the men.
Officials have been able to establish contact with the workers.
Authorities have also brought fresh and more sophisticated drilling equipment from Delhi to speed up the rescue operations, they told BBC Hindi.
The machine was airlifted to the Himalayan town of Uttarkashi by the Indian Air Force on Wednesday.
The workers are trapped some 200m into the tunnel and none of them are injured, officials said. Rescuers have been providing the men with food, water and oxygen through pipes for the last 72 hours.
But it is still not clear how much longer it would take to bring them out of danger.
“The rescue operations are on going round the clock each day. We are making every effort to bring the men out,” Karam Veer Singh, who is part of the team heading the efforts, told BBC Hindi.
On Tuesday the state government had decided to drill and insert a metal pipe of 900mm diameter through the debris to reach the workers. The workers could then squeeze through the pipe to safety, it was assessed.
Source: bbc.com