The Bhilangna is a major tributary of the:

The Bhilangna river is a major tributary of the Bhagirathi, one of the two headstreams of the Ganga, in the Tehri Garhwal district of Uttarakhand.

Course of the Bhilangna:

• It rises from the Khatling glacier, at the base of the Garhwal Himalayas, at about 3,700 metres.
• It flows south-west through the Ghansali area.
• It joins the Bhagirathi at the old town of Tehri (now submerged), within what is now the reservoir of a major dam.

The Bhilangna valley:

• The valley is known for its beauty and trekking routes, such as the Khatling glacier trek and the route to the Sahastra Tal lakes.
• The area is home to villages that practise traditional mountain agriculture.

Hydroelectric development:

The Bhilangna basin has several small and medium hydroelectric projects, which have raised concerns about their effects on the fragile Himalayan environment.

The Bhagirathi river system:

• The Bhagirathi rises from the Gangotri glacier at Gaumukh.
• It flows through Gangotri, Harsil and Uttarkashi.
• After receiving the Bhilangna, it flows on to meet the Alaknanda at Devprayag, where the Ganga is formed.

The Alaknanda system:

The Alaknanda rises from the Satopanth and Bhagirath Kharak glaciers and receives several tributaries, such as the Dhauliganga, Nandakini, Pindar and Mandakini, at a series of sacred confluences.

Environmental concerns:

The upper Bhagirathi valley from Gaumukh to Uttarkashi was declared the Bhagirathi Eco-Sensitive Zone in 2012, to protect the river from excessive construction and hydropower projects.

Why not the other options?

• ✗The Alaknanda is the other headstream of the Ganga, with its own tributaries.
• ✗The Yamuna and the Sharda (Kali) are separate rivers of Uttarakhand, flowing to the plains independently.