The authorities in Uttarakhand said all 40 construction workers, trapped after a portion of an under-construction tunnel collapsed on Sunday, remain unharmed.
Communication is established with workers and food and oxygen are provided through pipe.
Rescue and relief operations continued on Monday morning after the under-construction tunnel on the Yamunotri National Highway partially collapsed.
Silkyara Control Room said on Monday that the people trapped were contacted through walkie-talkies.
On Monday, Uttarakhand CM Pushkar Singh Dhami reached the Silkyara tunnel to take stock of the situation.
The State Disaster Response Force (SDRF) and the National Disaster Response Force (NDRF), along with police and local administration personnel, are working to rescue the trapped. An escape passage is being created to reach the trapped workers, and the distance to reach those trapped is approximately 60 meters.
The trapped workers hail from Bihar, Jharkhand, Uttar Pradesh, West Bengal, Odisha, Uttarakhand and Himachal Pradesh, officials said.
