Union cabinet has approved construction of a 4-lane access-controlled greenfield corridor from Gohpur (NH-15) to Numaligarh (NH-715), including a 15.79-km road-cum-rail underwater tunnel under the Brahmaputra, at a total capital cost of Rs 18,662 crore, the government said.The total project length will be about 33.7 km, and will be implemented on an Engineering, Procurement and Construction (EPC) mode.The project is expected to be India’s first underwater road-cum-rail tunnel and the world’s second, and is aimed at strengthening connectivity across Assam and the broader Northeast region.Currently, travel between Numaligarh and Gohpur via the existing Kaliabhomora bridge route is about 240 km and takes nearly six hours, passing through areas including Kaziranga National Park and Biswanath Town.The new greenfield corridor with the tunnel is aimed at significantly improving connectivity, reducing logistics costs and improving freight movement efficiency across Assam, Arunachal Pradesh, Nagaland and other northeastern states.Multimodal integration and network connectivityThe corridor will integrate with two major national highways — NH-15 and NH-715 — and two railway sections:

The project will also enhance multimodal connectivity by linking:

It will also improve access to four major railway stations, two airports and two inland waterway terminals, enabling faster movement of goods and passengers.Strategic and economic impactThe government said the project will play a key role in strategic connectivity, regional economic growth and trade expansion while strengthening links between major economic centres.The project is expected to generate about 80 lakh person-days of direct and indirect employment, supporting economic activity and development in surrounding regions.The tunnel component will include– Twin tube TBM tunnel with rail provision in one tube — 15.79 km, Road cut-and-cover section (1.26 km) and Rail cut-and-cover section (4 km). The project will connect key economic zones, industrial areas, social districts, tourist hubs including Kaziranga National Park, and major urban centres including Numaligarh, Tezpur, Gohpur, Dibrugarh and Itanagar.