PM Modi has inaugurated the Atal Tunnel at Rohtang at an altitude of above 3,000 metres in Himachal Pradesh.
Refer this link to read more about Himalayan passes and rivers
https://www.civilsdaily.com/the-northern-and-northeastern-mountains-part-1/
Atal Tunnel
- The 9.02 km-long-tunnel, built by the Border Roads Organisation (BRO), is the world’s longest highway tunnel and connects Manali to Lahaul-Spiti valley.
- It provides all-weather connectivity to the landlocked valley of Lahaul-Spiti, which remains cut-off for nearly six months in a year as the Rohtang Pass is usually snow-bound between November and April.
- Before the tunnel construction, the Lahaul Valley used to remain closed for vehicular movement due to bad weather conditions.
- It reduces the distance by 46 km between Manali and Leh and the travel time by about 4 to 5 hours. It is expected to boost tourism and winter sports in the region.
- The tunnel, also significant from the military logistics viewpoint, will provide better connectivity to the armed forces in reaching Ladakh.