An avalanche on February 7 had caused large-scale damage to the project besides totally demolishing the Rishiganga hydel project at Raini village in Chamoli district.
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.