Why in News?
The Cabinet Committee on Economic Affairs has approved India’s first underwater road-cum-rail tunnel project under the Brahmaputra River in Assam.

Key Highlights:
Project Type:
- Underwater twin-tube road-cum-rail tunnel
Location:
- Under Brahmaputra River, Assam
Significance:
- First-of-its-kind underwater tunnel in India
Brahmaputra river
Brahmaputra River:
- Originates from Chemayungdung Glacier near Lake Mansarovar (Tibet)
- Known as:
- Yarlung Tsangpo (Tibet)
- Siang/Dihang (Arunachal Pradesh)
- Jamuna (Bangladesh)
Key Features:
- Great Bend near Namcha Barwa
- Famous river islands:
- Majuli (largest inhabited)
- Umananda (smallest inhabited)
Biodiversity Importance:
- Supports Kaziranga National Park
