All 41 workers trapped in the collapsed Uttarkashi tunnel have been rescued after 17 days of multi-agency rescue efforts that included horizontal and vertical drilling.
Here is a timeline of how the rescue efforts unfolded over the past two weeks:
November 12: A landslide strikes the Brahmkhal-Yamunotri highway on the day of Diwali, resulting in the partial collapse of the Silkyara-Dandalgaon under-construction tunnel around 5.30am and 41 workers at the site get trapped.
A multi-agency rescue operation begins with teams comprised of personnel from NDRF, SDRF, BRO, ITBP and NHIDCL, which was executing the project. Authorties ensure supply of oxygen, food and electricity to the trapped workers
November 13: Recue team manages to contact trapped workers through a pipe used to supply oxygen. More rubble keeps falling with the debris accumulation spreading from 30 metres to 60 metres.
November 14: Preparations begin to insert 800mm diameter steel pipes through the rubble using an auger machine via horizontal digging. More rubble falls and two workers suffer minor injuries.
November 15: NHIDCL asks for a state-of-the-art auger machine, which is airlifted from Delhi to speed up the operation after the earlier machine is unable to perform the required task.
November 16: New diesel-driven 1,750-horse power American auger machine starts drilling through rubble after midnight.
November 17: Around afternoon, drilling team clears 24 metres of rubble out of the total 57-metre rubble stretch by the afternoon and inserts four steel pipes. Fifth pipe hits an obstacle.
Another state-of-the-art auger machine brought to speed up the rescue operations. However, operation gets suspended after a cracking sound is heard in the tunnel, sparking worries about further collapse of rubble.
November 18: Experts warn of further collapse of debris due to vibrations created by the auger machine that could risk the lives of the rescue personnel. Drilling remains halted and PMO officials mull alternative options.
They along with experts chalk out five evacuation plans that could be implemented simultaneously. One of the plans was to drill vertically through the top of the tunnel.
November 19: Union minister Nitin Gadkari reviews the rescue operation and says horizontal drilling appeared to be the best bet. Drilling remains suspended.
November 20: PM Narendra Modi dials CM Pushkar Dhami to take stock of the operations. A boulder blocking the progress of the auger machine keeps the drilling suspended.
November 21: The first video of the trapped workers released. It showed the workers, donning yellow and white helmets, talking to each other.
Rescue team simultaneously begings drilling at the other end of the tunnel in Balkot though experts said it could take up to 40 days to reach the workers. Horizontal drilling from the Silkyara end using auger machine begins.
November 22: Horizontal drilling reaches about 45 metres with only 12 more metres remaining. Ambulances, doctors and hospital beds on standby. Auger machine hits some iron rods overnight.
November 23: The iron rods blocking the way removed after six hours and the drilling reaches 48 metres. Drilling halted again after cracks appeared in the platform where the drilling machine rests.
November 24: Drilling which resumes after the auger machine is restarted, gets suspended again after the machine hits a metal girder.
November 25: The auger machine blades are stuck in the debris, with the rescue team being forced to go for alternate options that could take several days.
Officials decide to manually bore through the remaining rubble and simultaneously drill vertically 86 metres from above.
November 26: Vertical drilling completes 19.2 metres of 83 metres and 700mm pipes are being inserted.
November 27: Rat-hole miners join the rescuers to dig through around 10 metres of horizontal rubble. Vertical drilling from above reached a depth of 36 metres.
November 28: Rat-hole mining experts break through the last stretch of the rubble at about 7 pm. Trapped workers are brought out on wheeled-stretchers one by one with all 41 men being evacuated safely.
Also Read: How Uttarkashi tunnel collapse has triggered faith, security and environmental concerns