What is the India–China border dispute about?

India and China share a long Himalayan border of around 3,488 kilometres that has never been properly agreed upon. Instead, the two sides are separated by the Line of Actual Control, or LAC, and they disagree about where exactly it runs.

The two biggest areas of dispute are Aksai Chin in the west, which China controls and India claims as part of Ladakh, and Arunachal Pradesh in the east, which India governs and China claims as “South Tibet”. The countries fought a war in 1962, which India lost.

Tensions flared again in June 2020, when Indian and Chinese soldiers clashed in the Galwan Valley in Ladakh. Twenty Indian soldiers were killed, along with an undisclosed number of Chinese troops. It was the deadliest clash in decades and led to a long military standoff.

Relations have thawed somewhat since late 2024, when the two sides agreed on patrolling arrangements at key friction points, and Prime Minister Modi travelled to China for the Shanghai Cooperation Organisation summit in 2025. Flights and pilgrim routes have reopened. Even so, the core border question is far from solved, and both sides keep large numbers of troops nearby.