Prime Minister Narendra Modi will inaugurate the strategically important all-weather Atal Tunnel on Saturday, which reduces the distance between Manali and Leh by 46 km and the travel time by four to five hours, at Rohtang in Himachal Pradesh.

Set to be the world’s longest highway tunnel above the altitude of 10,000 feet (3000 metres), the tunnel, built at an estimated cost of Rs 3,500 crore, is named after former prime minister Atal Bihari Vajpayee, who had announced the project on June 3, 2000.

However, the idea of constructing a tunnel beneath the Rohtang Pass at 13,000 feet was first envisaged in 1983 and its construction received an impetus after the Kargil conflict.

On May 26, 2002, after the detailed feasibility study in 1987, Vajpayee laid the foundation of the tunnel and the access road to the tunnel costing Rs180 crore. 

The work of the tunnel was entrusted to the Border Roads Organisation (BRO) after receiving the final technical approval in 2003. 

In 2009, a joint venture of Shapoorji Pallonji Group-run Afcons and Strabag of Austria won the Engineering Procurement & Construction (EPC) tender for Rs 1,458 crore from Border Road Organisation.

Originally, the project was estimated to be complete by February 2015 and designed to be 8.8 km long but the GPS readings taken on completion shows it to be 9 km long. 

The UPA chairperson Sonia Gandhi, as the National Advisory Council chief, laid the foundation stone of the Atal tunnel (earlier called Rohtang Tunnel) in 2010, in the presence of the then Defence Minister AK Antony and many other politicians and officials at Dhundi, about 25km north of Manali town.

Following which the drilling of the Rohtang Tunnel through the Himalayan ranges began on 28 June 2010 at the South Portal, 30 km (19 mi) north of Manali.

Later some of the anchoring and slope stabilisation work was subcontracted to Spar Geo Infra Pvt Ltd.

Over the years, sometimes owing to cloudburst, sometimes due to avalanche and majorly due to worker’s strike on several occasions that date of completion kept getting pushed back further and further. 

However, in October 2017 the digging work finally came to a conclusion with both the ends of the tunnel finally meeting and Nirmala Sitharaman, the Defence Minister, visited the place.

From November 22 2017, it was decided to allow patients to be carried through the under-construction tunnel only in the gravest of emergency when the helicopter service was not available. 

Since then it has been used for several emergency situations. On September 30, 2018, over 5,000 people including tourists and workers who had stranded in Lahaul, Spiti and along the Keylong-Leh highway were evacuated through the Atal tunnel.    

A year later, bus services trial started through the yet-to-be-complete tunnel on November 17. And on December 25 in the same year, the tunnel was officially renamed as Atal tunnel to commemorate Atal Bihari Vajpayee on his 95th birth anniversary.

In February this year, Atal tunnel was closed completely for all kinds of movement, including for ambulances, due to ongoing full-width paving.  

The ongoing COVID-19 crisis too delayed the inauguration of the tunnel, which was originally planned to complete under six years. But on October 3, the much-anticipated tunnel will finally start functioning in its entirety.