The Sela Tunnel under the Balipara-Charduar-Tawang Road Upgradation Project is likely to be completed by the end-December 2023.
Currently, about 96 per cent of work has been completed on the same.
The tunnel has been excavated below the 4,200 m (13,800 ft) Sela Pass, which is often closed due to snowfall and landslides.
It involves construction of 11.315 km long twin tunnel and 8.780 km approach roads to ensure all-weather connectivity between Guwahati in Assam and Tawang.