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 3,500km 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 Tuesday at the high-altitude tunnel, which is part of a route designed to rapidly improve connectivity between Srinagar, the main city in Indian-administered 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 13.14km 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 3,528m Zojila Pass.

The project is part of a broader network of four major tunnels, including the 6.5km Sonamarg tunnel, a US$712 million (S$916 million) initiative expected to be fully operational by 2028.

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

The 272km 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.

Rebel groups demand independence for Kashmir, or a merger of the heavily militarised territory with Pakistan. AFP