In May 1954, India and China signed the Panchsheel Treaty (Five principles of peaceful co-existence). Despite this in January 1959 Chinese Premier Zhou Enlai lays claim to more than 40,000 sq miles of Indian territory in Ladakh and NEFA (present day Arunachal Pradesh). Talk to sort out the border issue in April 1960 between Chinese Premier Zhou Enlai and Indian Prime Minister Nehru, ended in a dead end at New Delhi. On 8th September 1962 the Chinese made their first incursion into Indian Territory in the Eastern sector. Later the then Prime Minister of India Pandit Jawaharlal Nehru said that the Indian Army had instructions to “free our territory” and the troops were given the freedom to exercise their judgment to use force whenever they found it necessary.
However, on 11th September 1962 when the Chinese incursions did not stop the patrols were given the permission to fire at any armed Chinese entering Indian Territory. This was the beginning of Sino-Indian war which began on 20th October 1962. At the time, nine divisions from the eastern and western commands were deployed by India along the Himalayan border with China. None of these divisions was up to its full troop strength, and all were short of artillery, tanks, equipment, and even adequate articles of clothing.
On 19th November 1962, China declared a cease fire following which firing along the border stopped. After administering a blistering defeat in 1962, the Chinese forces withdrew 20 km behind the McMahon Line, which China called “the 1959 line of actual control” in the Eastern Sector, and 20 km behind the line of its latest position in Ladakh, which was further identified with the “1959 line of actual control” in the Western Sector. The Sino-India war is notable for the harsh conditions under which it was fought. Combat took place at an altitude of 4,250 meters. During the war, neither country deployed the Air Force or Navy. Later in 1993 and 1996 both India and China signed the Sino-Indian Peace and Tranquility Accords agreeing to maintain peace and harmony along the LoAC.