Both nations lay claim to the Aksai Chin region of northeastern Kashmir, which fell into Chinese control during the Sino-Indian War of 1962.

Negotiations took place in Delhi from December 1953 to April 1954 between the Delegation of the PRC Government and the Delegation of the Indian Government on the relations between the two countries with respect to the disputed territories of Aksai Chin and South Tibet.

China attacked some of these outposts, and thus the Sino-Indian War began, which India lost, and China withdrew to pre-war lines in eastern zone at Tawang but retained Aksai Chin which was within British India and was handed over to India after independence.

Today Kashmir denotes a larger area that includes the Indian-administered state of Jammu and Kashmir ( which consists of the divisions: the Kashmir valley, Jammu and Ladakh ), the Pakistani-administered Gilgit – Baltistan and the Azad Kashmir provinces, and the Chinese-administered regions of Aksai Chin and Trans-Karakoram Tract.

The Karakash River ( Black Jade River ) which flows north from its source near the town of Sumde in Aksai Chin, to cross the Kunlun Mountains.

: " By 1956 – 57 they had completed a military road through the Aksai Chin area to provide better communication between Xinjiang and western Tibet.

The region is divided among three countries in a territorial dispute: Pakistan controls the northwest portion ( Northern Areas and Azad Kashmir ), India controls the central and southern portion ( Jammu and Kashmir ) and Ladakh, and China controls the northeastern portion ( Aksai Chin and the Trans-Karakoram Tract ).

Geographically part of the Tibetan Plateau, Aksai Chin is referred to as the Soda Plain.

India claims those areas, including the area " ceded " to China by Pakistan in the Trans-Karakoram Tract in 1963, are a part of its territory, while Pakistan claims the entire region excluding Aksai Chin and Trans-Karakoram Tract.

In June 1980 China made its first move in twenty years to settle the border disputes with India, proposing that India cede the Aksai Chin area in Jammu and Kashmir to China in return for China's recognition of the McMahon Line ; India did not accept the offer, however, preferring a sector-by-sector approach to the problem.

At its western end is the Aksai Chin region, an area the size of Switzerland, that sits between the Chinese autonomous region of Xinjiang and Tibet ( which China declared as an autonomous region in 1965 ).

The Aksai Chin region is a desert of salt flats around 5, 000 metres above sea level, and Arunachal Pradesh is mountainous with a number of peaks exceeding 7000 metres.

The cause of the war was a dispute over the sovereignty of the widely separated Aksai Chin and Arunachal Pradesh border regions.

Aksai Chin, claimed by India to belong to Kashmir and by China to be part of Xinjiang, contains an important road link that connects the Chinese regions of Tibet and Xinjiang. China's construction of this road was one of the triggers of the conflict.

The boundaries at its two extremities, Pangong Lake and Karakoram Pass, were well defined, but the Aksai Chin area in between lay undefined.

claimed that Aksai Chin had been part of the Indian Ladakh region for centuries, and that the border ( as defined by the Johnson Line ) was non-negotiable.

In 1956 – 57, China constructed a road through Aksai Chin, connecting Xinjiang and Tibet, which ran south of the Johnson Line in many places.

Aksai Chin was easily accessible to the Chinese, but access from India, which meant negotiating the Karakoram mountains, was more problematic.

At the time, Chinese officials issued no condemnation of Nehru's claims or made any opposition to Nehru's open declarations of control over Aksai Chin.

He later argued that Aksai Chin was already under Chinese jurisdiction, implying that there was therefore no contradiction with his earlier statement, since China did not regard the region as " Indian controlled ", and that since the British hand-over, China had regarded the McCartney MacDonald Line as the relevant border.

In 1950, the Chinese People's Liberation Army annexed Tibet and later the Chinese extended their influence by building a road in 1956 – 67 and placing border posts in Aksai Chin.

The Indian government's 1950 maps show the Sino-Indian border using undemarcated lines and the Aksai Chin frontier is labelled " boundary undefined ".

The Indian government's 1954 maps unilaterally delimited the Sino-Indian border in the Aksai Chin, and Sino-Indian borders are no longer indicated as undemarcated.

In August 1959, the People's Liberation Army took an Indian prisoner at Longju, which had an ambiguous position in the McMahon Line, and two months later in Aksai Chin, a clash led to the death of nine Indian frontier policemen.

The disputed territory of Aksai Chin is to the west, and its boundary with that region is not defined.

Aksai Chin (;, Aksā ' ī cina ; Urdu: اکسائی چن ) is one of the two main disputed border areas between China and India, the other being Arunachal Pradesh.

The etymology of Aksai Chin is uncertain regarding the word " Chin ".

Aksai Chin is one of the two main disputed border areas between India and China.

The line that separates Indian-administered areas of Jammu and Kashmir from Aksai Chin is known as the Line of Actual Control ( LAC ) and is concurrent with the Chinese Aksai Chin claim line.

Topographically, Aksai Chin is a high altitude desert.

In the north, the Kunlun Range separates Aksai Chin from the Tarim Basin, where the rest of Hotan County is situated.

The northern part of Aksai Chin is referred to as the Soda Plain and contains Aksai Chin's largest river, the Karakosh, The river, which receives meltwater from a number of glaciers, crosses the Kunlun farther northwest, in Pishan County and enters the Tarim Basin, where it serves as one of the main sources of water for Karakax and Hotan Counties.

The largest of them is that of the Aksai Chin Lake, which is fed by the river of the same name.

Upon independence in 1947, the government of India used the Johnson Line as the basis for its official boundary in the west, which included the Aksai Chin From the Karakoram Pass ( which is not under dispute ), the Indian claim line extends northeast of the Karakoram Mountains through the salt flats of the Aksai Chin, to set a boundary at the Kunlun Mountains, and incorporating part of the Karakash River and Yarkand River watersheds.

Local authorities in Ningxia point out that their model of Aksai Chin is part of a tank training ground, built in 1998 or 1999.

On 20 October, Chinese soldiers attacked India in both the North-West and North-Eastern parts of the border and captured vast portions of Aksai Chin and Arunachal Pradesh.

From there, it runs east along the Kunlun Mountains, before turning southwest through the Aksai Chin salt flats, through the Karakoram Mountains, and then to Panggong Lake.

Zhou later argued that as the boundary was undemarcated and had never been defined by treaty between any Chinese or Indian government, the Indian government could not unilaterally define Aksai Chin's borders.

As a consequence of their non-recognition of the McMahon Line, China's maps showed both the North East Frontier Area ( NEFA ) and Aksai Chin to be Chinese territory.

For instance, a professor of formal logic called Chin Yueh-lin – who was then regarded as China ’ s leading authority on his subject – was induced to write: “ The new philosophy Marxism-Leninism, being scientific, is the supreme truth ”.

The name ' Qin ' ( pronounced as ' Chin ') is believed to be the etymological ancestor of the modern day European name of the country, China.

As a word of Turk origin, aksai literally means " white brook " but whether the word Chin refers to Chinese or pass is disputed.