Why are Chinese and Indian troops fighting in a remote Himalayan valley?

At Galwan, India completed a road leading to an airfield in October despite Chinese objections. India says it is operating on its side of the LAC.

What has happened in the past?

The deaths were the first since hundreds died on both sides in a major border clash in 1967 between the nuclear-armed neighbours, which are the world's two most populous countries.

India and China fought a brief war in Ladakh and in northeastern India in 1962. Mutual distrust has occasionally led to flare-ups since. Infrastructure work near or within disputed territories is frequently followed by increased tension.

The LAC largely follows a ceasefire line after the 1962 war, but the two sides disagree on where it lies.

The last major dispute was in 2017 on the remote Doklam plateau near the borders of India, Bhutan and China. After a tense standoff, both sides agreed to an "expeditious disengagement" of troops, according to India's foreign ministry.