Indian engineers broke through the final rock section in the strategic Zojila tunnel through a Himalayan mountain on Tuesday, a milestone in providing all-weather access to the frontier Ladakh region with China.

India and China, the world’s two most populous nations, are intense rivals competing for strategic influence across South Asia.

Ties have thawed since a 2020 border clash, but their 3,500-kilometre frontier has been a perennial source of tension.

The tunnel forms part of a broader infrastructure push, creating a link with roads and railways that will allow trade, troops and supplies to move year-round from India’s sweltering lowland plains to the soaring icy border zones.

“This is not just a tunnel but a lifeline,” said India’s minister of roads, Nitin Gadkari, during a breakthrough ceremony on Tuesday at the high-altitude tunnel, which is part of a route designed to rapidly improve connectivity between Srinagar, the main city in Indian occupied Kashmir, and Leh, Ladakh’s key city.

At present, road travel between the cities is blocked during winter due to heavy snowfall, which can often rise higher than a truck.

Diggers cut through the final stretch of rock in a milestone in the creation of the 13.14-kilometre Zojila tunnel, which will connect two sides otherwise cut off by snow during the bitter winters.

More than 3,000 workers have been involved since 2020 in excavating the tunnel, which passes beneath the 3,528-metre Zojila Pass.

Gadkari pressed a button to remotely trigger the final blast, connecting tunnels dug from both sides and creating what will be India’s longest road tunnel.

“We have worked for this tunnel day and night in challenging weather conditions, and completed it without any accident,” project engineer Manmohan Singh told AFP.

The project is part of a broader network of four major tunnels, including the 6.5-kilometre Sonamarg tunnel, a $712-million initiative expected to be fully operational by 2028.

India has also developed a $3.9-billion railway line connecting the lowland plains with occupied Kashmir, including the construction of the Chenab Rail Bridge, currently the highest of its kind in the world.

Prime Minister Narendra Modi opened the railway route in June 2025.

The 272-kilometre railway begins in the garrison city of Udhampur, headquarters of the army’s northern command, and runs through Srinagar.

Muslim-majority Kashmir has been divided between India and Pakistan since their independence from British rule in 1947, and both claim the Himalayan territory in full.