Prime Minister Narendra Modi inaugurated the strategic Atal highway tunnel in Himachal Pradesh on 3 October 2020.

The 9.02 km long horseshoe-shaped single-tube, two-lane tunnel -- the world's longest motorable tunnel at over 3,000 mtr above sea level, came up under the 3,978 mtr Rohtang Pass in the Pir Panjal range some 30 km from Himachal Pradesh. The all-weather tunnel can take any military traffic, even armoured vehicles.

The project undertaken by the Border Roads Organisation (BRO) was completed after 10 years with an outlay of Rs 3,200 crore.

A length of 587 mtr across the Seri-nullah or rivulet zone took four years and the balance 8.4 km took almost the same time. All the major works have been completed. Now cleaning and final touches are going on inside the tunnel.

For at least two years BRO will regulate movement of vehicles through the tunnel. Later, it will be handed over to local civil authorities.

The tunnel will shorten the distance between the Himachal Pradesh tourist resort and Keylong, the headquarters of Lahaul-Spiti, by 46 km, shortening travel time by nearly three hours.

With maximum speed limit of 80 km per hour, the tunnel is expected to see traffic of 3,000 cars and 1,500 trucks a day.

The tunnel has consumed 12,252 tonne steel, 1,69,426 tonne cement and 1,01,336 tonne of concrete, and excavated 5,05,264 tonne of soil and rocks by adopting the latest Austrian tunnelling method for construction.

The construction contract of the tunnel was awarded to Strabag-Afcons, a joint venture between India-based Afcons Infrastructure and Austria's Strabag.

Chandigarh-based Snow and Avalanche Study Establishment (SASE) has designed mechanical structures to ensure safety of motorists by countering avalanches on both ends of the tunnel that remain under snow even during peak summer.

The tunnel's foundation stone was laid on 28 June 2010 in the Solang Valley near Manali.

The completion of the Atal tunnel is a key element in the Defence Ministry's attempts to make the entire 475 km long Manali-Keylong-Leh highway.