It began at the end of June when Indian troops stopped Chinese workers from carrying out a road-building project in a disputed border area. Both countries have about 3,000 soldiers on each side of the border in the area, which is also close to the mountainous country of Bhutan. In retaliation for the Indian move, China cut off access to a group of Indian pilgrims trying to cross a Chinese pass on their way to Mount Kailash, a sacred site in Tibet for Hindus and Buddhists.
Two parts of the border are the main focus of long-running disputes. The larger section lies to the east in a border area stretching between Bhutan and Myanmar. India's side of the border covers Arunachal Pradesh, but China has claims in the area, which it calls South Tibet. India controls the Tawang monastery on its side of the border, a source of contention because it is one of the holy sites for Tibetan Buddhists.
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The other main flashpoint on the two countries' border is to the west on India's border with the Chinese region of Xinjiang. The Aksai Chin area is administered by Hotan county in Xinjiang, but areas are also claimed by India as parts of the Ladakh region of the state of Jammu and Kashmir.
The current stand-off is over another area. It focuses on a remote pocket of land known in Chinese as Donglang which borders with the Indian state of Sikkim and Bhutan. The area is under Chinese control.
Disputes over the line of the border with Tibet are arguably a result of British colonialism.
A deal was reached in 1914 to mark out the border between what was then British-controlled India and Tibet – the so-called McMahon Line.
The agreement was never recognised by China, but it was open to a land swap deal in which India could keep what it claims on the eastern stretches of the two countries border, with China keeping Aksai Chin in the west. The western section of the border was non-negotiable for Beijing as it provided the best access into Tibet from the rest of China.
New Delhi rejected any suggestion of giving up territory in contested areas, deeming them inviolable parts of the nation's territory.
Chinese and Indian troops fought a war in 1962 after a series of skirmishes heightened tensions on the border, which largely ended in stalemate. Beijing argues the Convention of Calcutta, dated 1890, set out the Sikkim issue and that there should be no dispute about the territory on which China's troops were trying to build the road.
India and China have held 15 rounds of border talks since the mid-1990s, but any gains have been limited. The border is normally peaceful, with not a shot fired in over 50 years, but the disputes are far from settled.
Occasional flare-ups have occurred on the border in recent years, deepening the sometimes tense relations between China and India.
India complained of a "deep incursion" into its territory four years ago in which a platoon of about 30 Chinese soldiers entered the Daulat Beg Oldi area in the Depsang Valley of eastern Ladakh in Indian-administered Kashmir. Chinese and Indian soldiers stood barely 100 metres apart at times at this easternmost point of the Karakoram tange on the western sector of the China-India border. Both sides eventually withdrew.