Indian Prime Minister Narendra Modi inaugurated the tunnel through the Himalayas, helping to shorten the time to deploy troops to the border with China.

"We have been dedicated to developing border infrastructure. The whole country has never seen roads, bridges and tunnels of this scale," Prime Minister Modi announced after the inauguration of the mountain tunnel.

"In addition to helping the local people, this infrastructure will also bring great benefits to our men and women," added Modi.

Atal tunnel across the Himalayas, located on a highway running through Himachal Pradesh state, northern India.

The 9km long tunnel worth $ 400 million will shorten the journey through a rugged pass, prone to landslides of the Himalayas.

Tunnel construction can only be carried out for about 6 months a year due to the difficult terrain and freezing temperatures of the area.

The project is seen as part of New Delhi's effort to keep pace with China's infrastructure development across the border.

India's BRO Organization, which runs most strategic projects in the region, says it has built more in the past four years than it did a decade ago.

Tensions broke out on the Indo-China border, especially after the June 15 clash in the Galwan valley in the Himalayas, killing dozens of soldiers on both sides.

Indo-Chinese soldiers have fought in border areas many times over the years but do not use weapons or open fire.

Atal tunnel location.