China
In the 18th to 19th centuries, the Sikh Confederacy of the Punjab region in India was expanding into neighbouring lands. It had annexed Ladakh into the state of Jammu in 1834. In 1841, they invaded Tibet with an army and overran parts of western Tibet. Chinese forces defeated the Sikh army in December 1841, forcing the Sikh army to withdraw from Tibet, and in turn entered Ladakh and besieged Leh, where they were in turn defeated by the Sikh Army. At this point, neither side wished to continue the conflict, as the Sikhs were embroiled in tensions with the British that would lead up to the First Anglo-Sikh War, while the Chinese was in the midst of the First Opium War with the British East India Company. The Chinese and the Sikhs signed a treaty in September 1842, which stipulated no transgressions or interference in the other country's frontiers.[20]
I don't know what kind of history they teach you over there in India, no wonder almost every Indian think it was China who started the war in 1962.