The Atal Tunnel, named after former Prime Minister Atal Bihari Vajpayee, has officially been certified by the World Book of Records as the `World`s Longest Highway Tunnel above 10,000 Feet`.The 9.02 km long, strategically significant, Atal Tunnel, that runs under the `Rohtang Pass` was constructed on the Manali - Leh Highway under the challenging conditions of freezing temperatures in extremely difficult terrain. Construction of this tunnel has reduced the distance on Manali - Sarchu road by 46 km and travel time by four to five hours, providing all-weather connectivity on the Manali - Leh axis. 

During its construction, the most challenging task was to continue the excavation during heavy snowfall in winter. Excavation for tunnelling was done from both ends. However, as Rohtang pass closes during the winter, the north portal was not accessible during winter and the excavation was being done only from the south portal in winters. Only about one-fourth of the entire tunnel was excavated from the north end and three-fourths was excavated from the south end. There were more than 46 avalanche sites on approaches to the tunnel.

Other challenges to the progress of the tunnel included difficulties in disposing more than 8 lakh m³ of excavated rock and soil, heavy ingress of water (as much as 30 lakh litres per day in June 2012) that required constant dewatering, costlier treatment and slowed the progress of excavation from 5-metre per day to just half a metre a day and unstable rocks that slowed blasting and digging. But all challenges were eventually overcome to create this strategic asset for India.