The Sino-Indian War (1962)

At the Simla Convention, British India and Tibetan representatives drew the McMahon Line as the frontier between India and Tibet; Chinese representatives did not accept it, and China has never recognized the line. The western sector around Aksai Chin was never formally demarcated at all, leaving two differently drawn versions of the border that both successor states inherited.

Location: Simla, British India

After China incorporated Tibet in 1950-1951, the 1959 Tibetan uprising and its suppression sent the Dalai Lama and thousands of refugees into India, which granted him asylum. The decision — made on humanitarian grounds over Chinese objections — badly damaged the goodwill of the 1954 Panchsheel Agreement and hardened suspicion on both sides of the border.

Location: Tawang, India

Indian and Chinese forces clashed at Kongka Pass in Ladakh, with casualties on both side and disputed accounts of who fired first. In the following years, an extensive exchange of letters between Prime Minister Jawaharlal Nehru and Premier Zhou Enlai failed to reconcile the two countries' territorial claims.

Location: Kongka Pass, Ladakh

India began establishing military posts in territory it claimed along the disputed frontier, including in areas Chinese forces already patrolled. Indian planners judged that China would not respond with force — an assessment Indian post-war inquiries later found gravely mistaken — while China viewed the posts as creeping encroachment on its claimed territory.

Chinese forces attacked simultaneously in the western (Ladakh) and eastern (NEFA) sectors, overrunning Indian forward positions within days. Indian troops, poorly supplied for high-altitude warfare and operating under confused command, suffered heavy casualties and retreats in both theaters.

Location: Aksai Chin and the North-East Frontier Agency

During and after the war, the Indian government detained roughly 3,000 citizens and residents of Chinese descent at a camp in Deoli, Rajasthan — many held for years after the fighting ended, and some deported to China. Indian officials justified the measures as wartime security; historians and later official acknowledgments have treated the episode as one of the war's gravest civil-liberties consequences, and it remains a subject of Indian public reckoning.

Location: Deoli, Rajasthan, India

China's 24 October three-point ceasefire proposal — a mutual 20-kilometer (12-mile) withdrawal and return to the October 1959 line — was rejected by India, which objected to the preconditions. Fighting resumed in mid-November, with battles at Walong in the east and the Se La pass on the road toward the Assam plains, again going against Indian forces.

China declared a unilateral ceasefire and withdrew its forces to positions 20 kilometers (12 miles) behind its claimed line of actual control, ending the war after a month of fighting. China retained control of Aksai Chin — the territory at the heart of its western claim — a position unchanged to this day.

India declared its first National Emergency, Defence Minister Krishna Menon resigned under public pressure, and the government launched a massive defense expansion that doubled the army within a decade. The defeat ended Nehru's foreign policy premised on China-India partnership and pushed India toward closer ties with the Soviet Union and a nuclear program's intellectual foundations.

Location: New Delhi, India

The war's interpretation became a long-running debate: Neville Maxwell's "India's China War" (1970) argued that India's Forward Policy provoked the conflict, a view contested by Indian accounts, while the classified Henderson Brooks report on military failures was only partially made public in 2014. The border itself was never settled — agreements in 1993 and 1996 calmed the frontier, but standoffs at Doklam in 2017 and the fatal Galwan Valley clash of 2020 showed the 1962 dispute remains alive.