How Engineers Built the Atal Tunnel Under the Himalayas | India’s Engineering Marvel

Atal Tunnel | Rohtang Tunnel | Himalayan Tunnel Engineering | Tunnel Construction India | Pir Panjal Tunnel | Indian Engineering Before the Atal Tunnel was built, Rohtang Pass remained closed for around six months every year because of heavy snowfall, cutting off Manali’s connection with Lahaul-Spiti. To solve this problem, engineers built a 9.02 km tunnel beneath the Pir Panjal Himalayas, creating an all-weather route through one of India’s most challenging terrains. Construction used the NATM method and drill-and-blast technique, with excavation beginning simultaneously from the Manali and Sissu sides. But the real challenge came at the Seri Nala fault zone, where the rock was severely broken and around 8,000 litres of water started entering the tunnel every minute. Crossing this 587 metre section alone took more than four years. Engineers used thick layers of shotcrete and support systems, drilled deep holes to drain the water, and strengthened the rock using rock bolts and grouting. The tunnel was built with a horseshoe-shaped design and included a separate emergency escape tunnel for safety. After years of difficult construction, the 9.02 km Atal Tunnel was completed in 2020, transforming year-round connectivity between Manali and Lahaul-Spiti. This is the engineering story behind how India built a road straight through the Himalayas. #AtalTunnel #RohtangTunnel #IndianEngineering #HimalayanEngineering #TunnelConstruction #PirPanjal #EngineeringIndia #InfrastructureIndia #MegaProjectsIndia