India is set to build its first underwater road tunnel after the Cabinet Committee on Economic Affairs (CCEA), chaired by Prime Minister Narendra Modi, approved a major infrastructure project in Assam. The project involves constructing a four-lane access-controlled greenfield corridor between Gohpur on NH-15 and Numaligarh on NH-715, with a total capital outlay of INR 18,662.02 crore.
At the heart of the project is a 15.79-kilometre road-cum-rail tunnel beneath the Brahmaputra River. This will be India’s first underwater road and rail tunnel and only the second such integrated tunnel globally. The total corridor length will be 33.77 kilometres and will be developed under the Engineering, Procurement and Construction (EPC) mode.
Currently, connectivity between Numaligarh and Gohpur requires a nearly 240-kilometre journey via the Kaliabhomora bridge near Silghat, taking around six hours. The new corridor aims to drastically reduce travel time and distance, easing passenger and freight movement while bypassing congestion-prone stretches near Kaziranga and Biswanath.
The tunnel will feature a twin-tube Tunnel Boring Machine (TBM) design, with railway infrastructure housed in one tube. The project also includes 1.26 kilometres of road cut-and-cover and 4 kilometres of rail cut-and-cover construction. Designed for seamless multimodal connectivity, the corridor is expected to significantly boost regional development and strengthen Assam’s transport infrastructure.
