Sela Tunnel is a road tunnel at 3,000 metres (9,800 ft) which ensures all-weather connectivity between Guwahati in Assam and Tawang in Arunachal Pradesh. This tunnel is the longest bi-lane tunnel in the world at 13,000 feet. Situated 400 metres below the Sela Pass, the Sela Tunnel offers a vital passage, even during the winter season. The tunnel helps them move troops, weapons, and machinery quickly along the Sino-India border. It is connected with NH 13 by a new 12.4 km road and has reduced the distance between Dirang and Tawang by 10 km. It was inaugurated by PM Modi on 9 March 2024.Executed by the Border Road Organisation (BRO), the project features two tunnels and a link road. Tunnel 1 is a 980-metre-long single-tube tunnel, while Tunnel 2 is a 1,555-metre-long twin-tube tunnel, with one bi-lane tube for traffic and the other for emergency services. The link road between these tunnels spans 1,200 metres. The tunnel provides access to Tawang by an all-weather road in the western region of Arunachal Pradesh throughout the year.

The Sela Pass is a high-altitude mountain pass located on the border between the Tawang and West Kameng districts in the Indian state of Arunachal Pradesh. It has an elevation of 4170 m (13,700 ft) and connects the Indian Buddhist town of Tawang to Dirang and Guwahati. The pass carries the National Highway 13, connecting Tawang with the rest of India. The pass supports scarce amounts of vegetation and is usually snow-covered to some extent throughout the year. Sela Lake, near the summit of the pass, is one of approximately 101 lakes in the area that are sacred in Tibetan Buddhism. While Sela Pass does get heavy snowfall in winters, it is usually open throughout the year unless landslides or snow require the pass to be shut down temporarily. Sela pass is one of the highest motorable mountain passes in the world