The Sino-Indian War was a border war fought between communist China and India from 20 October to 21 November 1962 at the climax of Indo-Chinese tensions stemming from a Himalayan border dispute and from India's granting of asylum to the 14th Dalai Lama. While India had been among the first countries to grant recognition to the People's Republic of China, a crisis emerged after Prime Minister Jawaharlal Nehru of India claimed the Aksai Chin mountains for India; Chinese premier Zhou Enlai claimed that the MacCartney-MacDonald Line still stood as the Sino-Indian border, and, after the Chinese invasion of Tibet in 1950-51, the People's Liberation Army established military outposts in Aksai Chin and also build roads in the region from 1956 to 1967 to extend their influence. In 1959, after the failed Tibetan Uprising, India granted the Dalai Lama asylum in India, and, in October 1959, nine Indian frontier policemen were killed in a border clash with the Chinese.
India responded to these incidents by initiating a "Forward Policy" of constructing border outposts from 1960, hindering Chinese military patrols and logistics. From 1960 to 1962, the Indians rejected Chinese diplomatic overtures, and, on 30 April 1962, China re-commenced its controversial "forward patrols" along the border. On 20 October 1962, 80,000 Chinese troops launched a surprise invasion of the 2,000-mile-long Himalayan border in Ladakh, capturing Rezang La in Chushul in the west and Tawang in the east. Much of the combat between the Indians and Chinese occurred at high altitude, and both sides abstained from utilizing their aerial or naval forces due to the limitations of warfare 14,000 feet above ground level. As the United States and Britain refused to sell weaponry to non-aligned and socialist-leaning India, India instead purchased MiG fighter aircraft from the Soviet Union amid the Sino-Soviet split. On 21 November 1962, Zhou Enlai declared a universal ceasefire, with the Chinese advancing up to their 1960 claim line and consolidating their position in Aksai Chin, but the situation in Assam Himalaya remaining the same.