in 1962 China invaded two disputed region i.e. Ladakh and Arunachal. In Ladakh, the Indian army succeeded in retaliation but the Chinese army entered the Assam plains and captured some areas of Arunachal.

This was a huge setback for the Indian government and particularly the congress party. The first time no-confidence motion was introduced in the Lok sabha. The rift also originated in the opposition due to differences between USSR and china the communist party of India divided into CPI and CPI (Marxist)