At least 20 workers were killed and five others remained trapped for over 24 hours after an under-construction tunnel at NHPC's Teesta Stage-VI Hydroelectric Project collapsed in Samardung, South Sikkim, following a suspected methane gas explosion.

According to NHPC officials, 25 personnel were inside the tunnel when the incident occurred at around 1 pm on Monday. Rescue operations are underway, with NHPC officials at the site coordinating efforts and closely monitoring the situation.

Prime Minister Narendra Modi expressed anguish over the loss of lives in the incident and announced an ex gratia of Rs 2 lakh from the Prime Minister's National Relief Fund (PMNRF) to the next of kin of each deceased. The injured will be provided Rs 50,000 each.

Officials said the project team is working in close coordination with the district administration, the National Disaster Response Force (NDRF), the State Disaster Response Force (SDRF), and local authorities to carry out rescue operations. A specialised rescue team from the Directorate General of Mines Safety (DGMS) has also reached the site to assist in the operation.

They said a detailed investigation will be conducted to ascertain the cause of the incident and reiterated NHPC's commitment to extending full support to the rescue agencies and the families affected by the tragedy.

Union Minister of Power Manohar Lal Khattar expressed grief over the incident, saying, "My heart is deeply pained by the tragic incident at the under-construction Teesta Stage-VI Hydroelectric Project in Namchi, South Sikkim. I extend my deepest condolences to the families of those who lost their lives in this accident."

He said rescue and relief operations are being carried out on a war footing to safely evacuate those trapped inside the tunnel, with all possible assistance being provided by the local administration and the state government.

"I pray for the safe rescue of everyone and beseech God to grant strength to the bereaved families during this difficult time," the minister added.