Dehradun, Feb 11 : The rescue workers on early Thursday began drilling the tunnel vertically downward in what is seen as a new strategy to save 25-35 trapped people inside a tunnel of NTPC's Tapovan hydel project. "We are doing both excavation work and drilling the tunnel in our efforts to reach the trapped people," said DIG Nilesh Anand Bharne, who is also spokesperson of the Uttarakhand police. Ever since the excavation and digging work began inside the tunnel, the rescuers had been working on multi-pronged strategies in their desperate bid to open the tunnel which was blocked by the Sunday morning deluge. The rescuers have also used remote sensing technologies for geographical mapping of the tunnel. "We have also used geographical mapping of the disaster-hit tunnel in the operation," said Ridhim Agarwal, DIG SDRF. The rescue work slowed down on Tuesday due to the presence of heavy silt inside a tunnel of the disaster-hit Tapovan hydel project in Chamoli district of Uttarakhand. The DGP Ashok Kumar has stated that all possibilities will be explored to save the lives of the trapped people. After days of digging and excavation works, jawans of army, ITBP, NDRF and SDRF, who are engaged in the rescue works, had managed open a sizeable portion of the tunnel. But the presence of heavy silt and sludge inside the tunnel slowed down the rescue work, top government officials admitted. Rescuers also consulted NTPC officials to understand the complicated design of the tunnel. However, there is still no contact with the trapped people inside. The state government has stated that nearly 200 people were missing after the disaster and 34 bodies have been recovered. /IANS