The toll due to a blast in a tunnel that was being constructed in Sikkim’s Namchi district has increased to 25 after rescue teams recovered three bodies on Thursday, bringing a four-day search and recovery operation to an end. The tunnel was part of the Teesta Stage VI Hydroelectric Project of the National Hydroelectric Power Corporation in the Samardung area. The tunnel collapsed on Monday after a “sudden explosion of trapped or embedded suspected methane gas within the rocks, resulting in dense smoke and toxic gases”, the National Hydroelectric Power Corporation had said. Twenty-seven persons were trapped inside the tunnel, of whom two managed to come out safely, Chief Minister Prem Singh Tamang said. The National Hydroelectric Power Corporation has said that it will provide an ex-gratia payment of Rs 5 lakh to the next of kin of those who died.