The Sino-Indian War of 1962

The Sino-Indian War between China and India occurred in October–November 1962. A disputed Himalayan border was the main cause of the war. There had been a series of violent border skirmishes between the two countries after the 1959 Tibetan uprising, when India granted asylum to the Dalai Lama.  India initiated a defensive Forward Policy from 1960 to hinder Chinese military patrols and logistics, in which it placed outposts along the border, including several north of the McMahon Line, the eastern portion of the Line of Actual Control proclaimed by Chinese Premier Zhou Enlai in 1959.

Chinese military action grew increasingly aggressive after India rejected proposed Chinese diplomatic settlements throughout 1960–1962, with China re-commencing previously-banned "forward patrols" in Ladakh from 30 April 1962.  China finally abandoned all attempts of peaceful resolution on 20 October 1962, invading disputed territory along the 3,225 kilometres (2,004 mi) long Himalayan border in Ladakh and across the McMahon Line.  Chinese troops pushed back Indian forces in both theatres, capturing Rezang La in Chushul in the western theatre, as well as Tawang in the eastern theatre. The war ended when China declared a ceasefire on 20 November 1962, and simultaneously announced its withdrawal to its claimed "Line of Actual Control".

Much of the fighting took place in harsh mountain conditions, entailing large-scale combat at altitudes of over 4,000 metres (13,000 feet).  The Sino-Indian War was also notable for the lack of deployment of naval and aerial assets by either China or India.

As the Sino-Soviet split heated up, Moscow made a major effort to support India, especially with the sale of advanced MiG fighter-aircraft.  The United States and Britain refused to sell advanced weaponry to India, causing it to turn to the Soviet Union.

Location

China and India shared a long border, sectioned into three stretches by Nepal, Sikkim (then an Indian protectorate), and Bhutan, which follows the Himalayas between Burma and what was then West Pakistan.  A number of disputed regions lie along this border. 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 eastern border, between Burma and Bhutan, comprises the present Indian state of Arunachal Pradesh (formerly the North-East Frontier Agency).  Both of these regions were overrun by China in the 1962 conflict.

Most combat took place at high elevations. The Aksai Chin region is a desert of salt flats around 5,000 metres (16,000 feet) above sea level, and Arunachal Pradesh is mountainous with a number of peaks exceeding 7,000 metres (23,000 feet). The Chinese Army had possession of one of the highest ridges in the regions. The high altitude and freezing conditions also caused logistical and welfare difficulties; in past similar conflicts (such as the Italian Campaign of World War I) harsh conditions have caused more casualties than have enemy actions. The Sino-Indian War was no different, with many troops on both sides succumbing to the freezing cold temperatures.

                   https://en.wikipedia.org/wiki/Sino-Indian_War