Till Wednesday, about 120 metres of slush from the mouth of the tunnel was cleared and those trapped inside were stated to be located somewhere at the depth of 180 metres.
A joint team of ITBP, NDRF, SDRF and other agencies conducting rescue operations used drone cameras to see feasibility to enter beyond cleared site inside Tapovan tunnel.
Rescue teams comprising the Army, ITBP, NDRF and SDRF personnel have made little headway beyond 100 metres inside the tunnel as debris has been constantly flowing in.
With the hours ticking by inexorably, fears escalated about those missing since the disaster struck on Sunday morning, according to officials who stepped up efforts to locate survivors.
The 202 still missing include those working at hydel power project sites as well as villagers nearby whose homes were washed away with the force of the raging waters.