The Zojila tunnel, the world’s longest high-altitude bi-directional road tunnel, is a step closer to completion after a “breakthrough” was achieved in its construction on Tuesday — marking the end of the excavation phase.

The tunnel, which will connect Kashmir Valley and Ladakh throughout the year, is one of India’s most important strategic infrastructure projects.

We explain the significance of the project — for residents, who can soon expect all-weather connectivity, and for the armed forces, who can now reduce their dependence on air transport in the strategic Himalayan region.

The Zojila tunnel, situated at an altitude of 11,758 feet, is a 13-km road tunnel connecting Baltal (near Sonamarg) in Kashmir valley and Minimarg (near Drass) in Ladakh’s Kargil district. 

The tunnel bypasses the treacherous Zojila pass — a narrow, winding road at an elevation of 16,430 feet — that remains closed in the winters and is prone to landslides throughout the year.

This will reduce the distance from Sonamarg to Drass by 27 km and cut travel time by more than two hours. 

The tunnel forms the centrepiece of the 30.894-km Zojila project, which includes roads, bridges and tunnels aimed at ensuring year-round access to Ladakh.

The breakthrough

In tunnel construction, a “breakthrough” is the moment when excavation teams from opposite ends meet by cutting or blasting through the last section of rock or soil separating them. 

It marks the successful completion of the excavation phase of a tunnel. The excavation of the Zojila tunnel was completed by employing the New Australian Tunneling Method (NATM), which is suitable for the fragile Himalayan geology and variable rock conditions. 

“NATM relies on sequential excavation, immediate support measures such as rock bolting, and continuous geotechnical monitoring that allows engineers to respond flexibly to changing conditions during tunnelling,” said Siva Prasad Reddy, General Manager of Megha Engineering and Infrastructure Ltd (MEIL), the company that is constructing the project. “This approach has been critical to maintaining stability, safety, and construction progress in one of the most demanding underground environments in India.”

On Tuesday, as the last two metres of earth were blasted away to complete the “breakthrough”, Union Minister for Road Transport and National Highways Nitin Gadkari was present along with Chief Minister Omar Abdullah and Lt Governor Manoj Sinha.   

The Rs 6,800 crore project — which Prime Minister Narendra Modi laid the foundation stone for in May 2018 — was expected to be completed by September 2026. 

But the Covid-19 pandemic, the 2024 terror attack on the workers at the Z-Morh tunnel (now called the Sonamarg tunnel) and extreme weather conditions delayed the project. 

It is now targeted to be completed in February 2028. 

National Highways and Infrastructure Development Corporation Ltd is implementing it while MEIL bagged the tender for its construction. 

The Union Territory of Ladakh is connected to the rest of the country by two main highways — the Srinagar-Sonamarg-Leh highway and the Leh-Manali highway. 

Both roads, however, remain closed for almost six months every year owing to winter snow, avalanches and extreme weather conditions.

The people of the Union Territory have, therefore, long been demanding a road tunnel that connects Ladakh to Kashmir Valley. This tunnel promises to fulfill that demand.

Beyond this, however, the tunnel will also provide swift round-the-year mobility to defence forces in one of the country’s most sensitive border regions

All-weather connectivity to the region is especially important for defence forces as it will enhance their maneuverability in case of hostilities with China on the Line of Actual Control in Ladakh or with Pakistan on the Line of Control in Kargil.

For the defence forces, the all-weather highway is a strategic lifeline that will facilitate the seamless movement of personnel, military hardware, fuel and daily supplies — thus ending the long-standing reliance on expensive and vulnerable airlifts.  

Besides providing faster and more reliable connectivity, the all-weather highway is expected to significantly enhance military mobility by enabling quicker deployment of troops and equipment and reducing response times in the event of hostilities. 

The tunnel will also offer greater protection from enemy surveillance and artillery fire, vulnerabilities that were evident during the 1999 Kargil war when the key road link came under artillery fire.  

The other key tunnel that keeps the Srinagar-Leh highway operational throughout the year — the Z-Morh tunnel or Sonamarg tunnel — was completed and thrown open for traffic in January last year.  

What next

The Zojila tunnel project has several key components.

Besides the main Zojila tunnel are two smaller ones — one 457 metres long and the other 1,953 metres long — at Nilgrar. 

The larger Zojila project also comprises four bridges, an approach road from Sonamarg tunnel to Zojila tunnel, three vertical shafts — structures that provide ventilation and emergency access to the tunnel as it has no separate escape tunnel — a snow gallery and seven cut-and-cover structures. Most of these projects have already been completed.

“What is remaining is the balance works in the vertical shafts, we have already made the hole and have to widen 6.6 metres. It is the most challenging job we are up to and we expect it to complete in one-and-a-half years,” says Colonel A K Shivkumar, Zojila tunnel’s Project Manager. 

“We also have to do the balance work for the main tunnel. We have completed the inner concrete lining for 3 km and the rest of the stretch is expected to be completed in a year. In addition to this, we have to build a drainage system and set up a ventilation system, electrical system and a firefighting system.”

One of the three vertical shafts is 474.30 metres long and sits at an elevation of 3,481 metres — making it the  longest vertical shaft in India.