Assertion: Congress party won by a vast majority in the assembly elections of many states post-1971 war.

Reason: A decisive victory in the 1971 war was seen as a clear sign of India’s growing military prowess. Indira Gandhi's personal personality soared after the 1971 war.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

A decisive victory in the war led to national jubilation. Most people in India saw this as a moment of glory and a clear sign of India’s growing military prowess. As you would read in the next chapter, Indira Gandhi was the Prime Minister at this time. She had already won the Lok Sabha elections in 1971. Her popularity soared further after the 1971 war. After the war, assembly elections in most States took place, bringing large majorities for the Congress party in many states.