There is a continuous sound of heavy machinery at the mouth of the main tunnel of the Tapovan power station in India's Uttarakhand state.
Rescuers are desperately trying to reach about 35 workers trapped inside a tunnel after a glacier collapse.
It has now been more than 60 hours since a Himalayan glacier broke off in Uttarakhand, sweeping away bridges, breaking dams and sending a torrent of debris and water down a mountain valley.
So far, 31 bodies have been recovered but officials fear for the 165 who are missing at the two hydropower plants at Rishiganga and Dhauilganga.
They have only managed to reach about 100 meters into the mile-long tunnel at Tapovan until now.
The eight-metre-high tunnel is packed with debris and slush, and earthmovers have been continually removing it since operations began on Sunday.
But it's a slow process as only one can be used at a time.
Further inside the tunnel, it gets difficult as the height reduces to three meters, restricting bigger machinery.
The tunnel then descends almost 98 meters and joins another channel. At the end of this channel is where the men are trapped.
Over 1,000 military, paramilitary and specialists have been operating day and night at the site. Sniffer dogs are waiting to be taken in.
Manoj Rawat of the Indo-Tibetan Border Police, which is spearheading the operation, told Sky News: "All efforts are being made to rescue people trapped inside. We are working towards that.
"Nothing is established so far with any of them at the moment. All efforts of the country are being used here.
"Hope is there and we are doing everything possible."
But there is dismay and anger among some relatives of the men trapped inside.
Sati Negi and her elder sister have been keeping a vigil at the entrance since Sunday.
Her 30-year-old brother was working as a supervisor that fateful day.
"Why did they get him to work on Sunday and what safety did they provide? He has two small daughters and the family is distraught. We are just hoping and praying," she told Sky News.
Another relative said: "Authorities are just fooling us saying they have reached 70 to 80 metres, it's 1.7 miles long. The work is so slow and the machinery being used is insufficient."
A soldier who we cannot identify and whose son is also trapped said "there is no proper co-ordination and leadership".
"Each organisation is doing what they please," he added.
Deepak Nagwal, whose brother in law is also trapped, was highly critical of the authorities.
"No-one is telling the truth and giving exact information. At least tell us relatives what are the likely chances of finding anyone alive," he said.
At the other end of the tunnel, a specialist mountaineering unit of the army is rappelling down the sides of the dam.
"They don't expect anyone to survive. We are looking for bodies now," the colonel in charge said.
One of the soldiers who went to the bed of the river told us there is almost 25 feet of debris and mud.
"The tunnel is completely blocked from this end. No one can survive this," he said.
On Sunday morning a part of the Nanda Devi glacier broke, flooding the Dhaulli Ganga.
The force of the water was such that it broke two dams on its way, inundating the river and destroying everything in its path.
The havoc was caught on mobile phone footage by residents as they witnessed the wall of water, rock and dust roar down the river valley.
Both the plants have been flooded and heavily damaged and a small bridge between the two power projects has been destroyed, cutting off about a dozen villages.