Atal Tunnel is the longest highway tunnel in the World. The 9.02 Km long tunnel connects Manali to Lahaul-Spiti valley throughout the year. Earlier the valley was cut off for about 6 months each year owing to heavy snowfall.
The Tunnel is built with ultra-modern specifications in the Pir Panjal range of Himalayas at an altitude of 3000 Mtrs (10,000 Feet) from the Mean Sea Level (MSL).
The tunnel reduces the road distance by 46 Kms between Manali and Leh and the time by about 4 to 5 hours.
The South Portal (SP) of Atal Tunnel is located at a distance of 25 Km from Manali at an altitude of 3060 Mtrs, while the North Portal (NP) of the tunnel is located near village Teling, Sissu, in Lahaul Valley at an altitude of 3071 Mtrs.
It is horse shoe shaped, single tube double lane tunnel with a roadway of 8 Mtrs. It has an overhead clearance of 5.525 Mtrs.
It is 10.5-metre wide and has a 3.6 x 2.25 Mtrs fire proof emergency egress tunnel built into the main tunnel itself.
Atal Tunnel has been designed for traffic density of 3000 cars per day and 1500 trucks per day with max speed of 80 km/hr.
It has the state of the art electromechanical system including semi transverse ventilation system, SCADA controlled firefighting, illumination and monitoring system.
The decision to construct the strategic tunnel below the Rohtang Pass was taken on June 03, 2000 when Atal Bihari Vajpayee was the Prime Minister. The foundation stone for the Access Road to the South Portal of the tunnel was laid on May 26, 2002.
The Border Roads Organisation (BRO) worked to overcome major geological, terrain and weather challenges that included the most difficult stretch of the 587-metre Seri Nalah Fault Zone. The breakthrough from both ends was achieved on October 15, 2017.
The Union Cabinet on 24th December 2019 decided to name the Rohtang Tunnel as Atal Tunnel to honour the contribution made by the former Prime Minister Atal Bihari Vajpayee.