The workers got trapped after a portion of the tunnel collapsed on Diwali, November 12.
Saturday marked the 14th day since 41 labourers got trapped after a portion of an under-construction tunnel collapsed in Uttarakhand. The rescue operation, which began on the day of the collapse itself, has seen many rays of hope and several timelines stated by officials when the workers were "just hours away" from being saved.
Unexpected obstacles have, however, ensured that the best-laid plans of the rescue teams have been foiled and efforts to save the trapped workers will now resume only on Sunday, after the American drilling machine, which faced its third snag in as many days on Friday, is extracted from the tunnel. "This operation could take a long time," National Disaster Management Authority member Lt Gen (retd) said on Saturday.
"When you are working on a mountain, everything is unpredictable. We never gave any timeline," he added.
NDTV takes a look at the timeline of the rescue operation so far, the many occasions when it seemed there may be light at the end of the tunnel after all, and the obstacles that have had to be surmounted.
November 12: Disaster Strikes
The day of Diwali dawns and 41 labourers working on the Silkyara-Dandalgaon tunnel - part of the ambitious Char Dham project to enhance connectivity to the Hindu pilgrimage sites of Badrinath, Kedarnath, Gangotri, and Yamunotri - get trapped after a landslide hits the area, causing a portion of the structure to collapse around 5:30 am.
Rescue efforts are launched by the district administration and arrangements are made to supply oxygen and food to the trapped labourers via pipes. Food is pushed through to them using air compression.
Multiple agencies, including the national and state disasters response forces, Border Roads Organisation and the National Highways and Infrastructure Development Corporation Limited, join the rescue effort.
November 13: Rescue By Evening?
Contact is established with the trapped workers through a pipe meant to supply oxygen as well as walkie-talkies and they are reported to be safe. The workers are reported to be trapped around 55-60 metres from the Silkyara end of the tunnel and they are said to have a buffer of around 400 metres to walk and breathe.
While officials say they are hopeful of rescuing the workers by evening, Uttarakhand Chief Minister Pushkar Singh Dhami, who visits the site, says debris is continuing to fall, causing a delay in rescue operations.
November 14: Fresh Landslide
Steel pipes of 800- and 900-millimetre diameter are brought to the tunnel site. These pipes are meant to be pushed through the rubble and the workers are expected to crawl out through them.
An auger machine, which helps in horizontal drilling, is brought in to create a pathway for the pipes to go through the rubble.
Uttarkashi District Magistrate Abhishek Ruhela tells reporters that labourers could be evacuated by November 15. "If everything goes as planned, the trapped labourers will be evacuated by Wednesday," he says.
A platform is prepared for the auger machine, but it is damaged by a fresh landslide.
The trapped workers are supplied food and water as well as medicines after some of them complain of nausea and headache.
November 15: Protest At Site
The damaged platform for the auger machine is dismantled and new equipment, a much more powerful American auger, is sought, which leaves from New Delhi.
Several other workers involved in the construction of the tunnel protest at the rescue site over the delay in getting the trapped labourers out.
November 16: "Two-Three More Days"
Union Minister VK Singh visits the site and says it may take two-three more days for the rescue operation to be completed. The minister of state for road transport and highways adds the rescue could be finished sooner, even as early as November 17, but the government is keeping a longer timeline in mind to account for unexpected difficulties.
The minister also confirms that the rescue teams have spoken to foreign experts, including a firm that helped save 12 children and their football coach who were stranded in a cave in Thailand. Help is also taken from the Norwegian Geotechnical Institute.
The more powerful American auger, which is flown in using Indian Air Force aircraft, begins work on the site.
November 17: Loud Cracking Sound
Working overnight, the machine drills about 24 metres through the 57-metre stretch of rubble by the afternoon. Four pipes of six-metre length each are inserted but work comes to a halt around 2:45 pm when a "large-scale cracking sound" is heard by officials and the team working inside the tunnel.
Another auger machine is airlifted from Indore.
Doctors emphasise the need for comprehensive rehabilitation for the trapped workers, fearing that the prolonged confinement may necessitate both mental and physical recovery processes.
"It's a very traumatic event and their current mindset would be very apprehensive, filled with uncertainty about their future and their survival. They could be feeling fearful, helpless, traumatised and frozen in time. They might not be able to really process things," Dr Archana Sharma, consultant clinical psychologist at Sri Balaji Action Medical Institute, Delhi, tells PTI.
November 18: High-Level Meet
The rescue operation enters Day 7, but drilling does not resume as experts feel the vibrations created by the 1,750-horse power American auger inside the tunnel could cause more debris to fall.
The Union government holds a high-level meeting, where five rescue options are explored, including drilling vertically from the top of the hill and parallelly, from the side, to reach the workers.
A map emerges, pointing to an alleged serious lapse on the part of the company involved in the construction of the tunnel. According to the Standard Operating Procedure, all tunnels over 3-km long are supposed to have an escape route to rescue people in case there is a calamity. The map proves that such an escape route was also planned for the 4.5 km Silkyara tunnel, but never executed.
Family members of the 41 construction workers say they are worried after the drill stopped functioning the previous day. Some family members and other workers involved in the construction also tell NDTV that the labourers could have been saved much earlier if the escape route had been built.
November 19: Three More Days?
Drilling remains suspended while officials examine the option of getting to the workers by creating a hole from the top of the hill. Union minister Nitin Gadkari reviews the rescue operation and says drilling horizontally appears to be the best bet and that a breakthrough could happen within two-and-a-half days.
November 20: Hot Meal
Prime Minister Narendra Modi has telephonic conversation with Chief Minister Dhami and discusses the rescue operations. The PM emphasises that there is a need to keep up the morale of the stranded workers.
In some good news for the stranded labourers, rescuers manage to push a six-inch-wide pipeline all the way through the rubble. Khichdi is filled in bottles and sent to the workers, giving them their first hot meal in nine days.
Not much progress is made, however, with the heavy drilling machine.
November 21: Visuals Of Workers
The workers are seen for the first time in ten days as a camera inserted through a pipe captures their visuals. As officials speak to them and reassure them they will be brought out safely, the workers wave and communicate that they are doing okay.
In the evening, Additional Secretary Technical, Road and Transport, Mahmood Ahmed says the next few hours are crucial and, if all goes well, there could be some 'good news' in 40 hours.
November 22: Day Of Hope
This is the day when hopes are highest that the workers will be rescued by night. Ambulances are kept on standby and a special ward, with 41 beds, is made ready at a local health centre. Only 12 metres are said to separate the rescuers and the workers.
The drill hits an iron mesh in the night but officials still say that they could start bringing out the workers by 8 am the next day.
November 23: Another Snag
The iron mesh is removed in the morning and rescue operations resume. Director General of the National Disaster Response Force, Atul Karwal, says the workers will be rescued by night if no other obstacles are encountered.
The auger machine hits a metal pipe in the evening, however, which wraps itself around the drilling blades. Many hours are spent repairing the machine's blades, strengthening the platform on which the machine is operating and removing the metal girders and pipes which were obstructing the operation.
November 24: "Two More Pipes"
On Day 13, officials say only 10-12 metres of drilling is left and pushing in two more pipes may be enough to reach the labourers. Uttarakhand Secretary Neeraj Khairwal says a team of ground penetrating radar experts had been called in, who have said there are likely to be no major metal obstacles for the next five metres.
Asked whether the teams could reach the workers by Saturday morning, Additional Secretary Technical, Road and Transport, Mahmood Ahmed says it could happen even sooner if everything goes smoothly.
Drilling resumes in the evening but stops soon after when the auger machine encounters another metallic object.
"The auger machine has encountered some difficulty again and that's why it's being dismantled. Simultaneously, efforts are being made to get to the trapped workers manually. We are analysing the debris and trying to figure this out," an official said.
November 25: Manual Drilling Now
Uttarakhand Chief Minister Pushkar Singh Dhami says the auger machine is stuck inside the tunnel and a specialised piece of equipment is being flown in from Hyderabad to get it out.
"We are exploring all possible options. Prime Minister Narendra Modi is taking updates on a daily basis. We hope to complete the operations as soon as possible," he said.
No more automatic drilling will happen inside the tunnel and manual drilling will begin only on Sunday after the auger machine is pulled out.