Sikkim chief minister Prem Singh Tamang questioned the quality of the 1200 MW hydro power project on Friday, days after the dam was destroyed by flash floods in the Teesta river in the Chungthang area of the state.

The project was built during the 25-year rule of the Sikkim Democratic Front led by Pawan Chamling, which was in power until 2019. The state government has 60.08 % share in the project.

Teesta Urja, the second largest run-of-the-river hydro power project in India, was washed away due to flood caused by the breach in Lhonak lake in north-west Sikkim on the intervening night of Tuesday and Wednesday.

The 1,200 MW power project on Teesta river, one of the most dammed rivers in the country, is located between Chungthang and Mangan in Mangan district in north Sikkim and is the biggest of the nine working hydro projects on the river in Sikkim. Work on 15 dams is going on and another 28 are proposed over the river to tap its hydropower capacity of about 4,200 MW.

Addressing the media in Rangpo on Friday, Tamang said: “The substandard construction work at India’s second biggest hydel power project led to the destruction of the dam. This caused massive damages downstream.”

Tamang, who met people affected by the calamity, announced an ex-gratia payment of ₹4 lakh for families of those who died.

“Though there was a glacial lake outburst flood (GLOF) in north-west Sikkim, the damage to property was more because the dam collapsed. It was constructed in a substandard manner,” he said.

So far, 19 bodies have been recovered, Tamang said, adding that 103 people were still missing. A many as 25,000 people have been affected and 3500 rescued from areas, which were cut off because of extensive damage to roads and bridges, he said.

Tamang added: “The state government is getting full cooperation from the Centre. The state government is also trying to extend all possible help to the affected people. We are trying to rescue tourists stranded in north Sikkim.”

An estimated 3000 tourists remain stranded in north Sikkim.

“We are trying our best to evacuate tourists from places such as Lachen and Lachung which are completely cut off. Helicopters are not being able to fly due to inclement weather and even NDRF (national disaster response force) teams are waiting at Bagdogra airport (in West Bengal) to fly to North Sikkim,” he said.

The state government has decided to cancel tourist permits for places like Tsomgo Lake and Nathula. The measure has been taken to save resources like petrol and diesel, which can be channelised for rescue operations.

The national highway number 10 (NH-10), which is the lifeline of Sikkim, is damaged at several locations. Vehicles plying between Sikkim and West Bengal have to take long detours via Lava in Kalimpong district to get in or out of the areas affected by the disaster.