In the years 1967-1969, the People's Republic of China was engaged in practically simultaneous border conflicts with both of its most powerful neighbors; India and the USSR.
This had followed a steady decrease in relations with both nations; India and China had just fought a war in 1962 ending with a massive Indian defeat- but unlike that time, the Indians were now prepared, and had as many numbers on the border as the Chinese. The USSR, meanwhile, had generally had a split with their fellow Chinese Communists, urged on mainly by Mao's Cultural Revolution.
The Point of Divergence here takes place on October 10th, 1967. Instead of coming to a ceasefire agreement with China, Defense Minister Sardar Swaran Singh and Prime Minister Indira Gandhi convinced the President, Zakir Hussain, to authorize the sending of over 10,000 troops to Chola, while not declaring a full state of war. China responded likewise, leading to a series of tense border clashes, resulting in hundreds dead. As the months stretched on, however, tensions began to lower.
However, at the same time, to the North, the Sino-Soviet border conflict was now beginning to hot up. In late July 1968 (earlier than OTL), a Soviet patrol entered into a skirmish with a Chinese security patrol near Zhenbao Island. Neither side sustained any injuries. However, following this incident, a larger Chinese force attacked the island, resulting is sex deaths (all Chinese) and two injuries (both Russian).
In response to the fighting on the border, Mao announced that the Soviets had a deadline; surrender the 52,000 sq km of land the Soviets held in the Pakirs to China in 36 hours, or the Chinese forces would forcibly enter the territory.
In the South, meanwhile, this led to an increase of tensions, which suddenly broke with a massive firefight in Sikkim, at Chumo Yummo. When the smoke cleared, Chinese troops had broken through Indian positions and were now swiftly advancing towards Gangtok. Indian troops, however, immediately countered, cutting off the Chinese troops and surrounding them at Chumbo. However, further border conflicts broke out, at Jannu and Simvo.
After a swift meeting of Parliament, on August 1st, 1967, India declared a state of war on China.
Almost immediately after, with ten hours left before the Chinese deadline expired, the Soviet Union followed suit.
Now Asia faced a war.