Explanation:

A state of emergency in India refers to a period of governance under an altered constitutional setup that can be proclaimed by the President of India, when they perceives grave threats to the nation from internal and external sources or from financial situations of crisis. Under the advice of the cabinet of ministers and using the powers vested in him/her largely by Part XVIII of the Constitution of India, the President can overrule many provisions of the constitution, which guarantee fundamental rights to the citizens of India and acts governing devolution of powers to the states which form the federation. In the history of independent India, a state of emergency has been declared thrice.Originally at the beginning, National emergency could be declared on the basis of "external aggression or war" and "internal disturbance" in the whole of India or a part of its territory under Article 352. Such an emergency was declared in India in 1962 war (China war), 1971 war (Pakistan war), and 1975 internal disturbance (declared by Indira Gandhi). But after 44th amendment act 1978, National Emergency can only be declared on grounds of "External aggression or war", also called as External Emergency & on the ground of "armed rebellion", also called as Internal Emergency. The President can declare such an emergency only on the basis of a written request by the Cabinet headed by the Prime Minister. Such a proclamation must be laid before both houses of Parliament and the state of emergency expires after one month unless approved within that time by both houses sitting and voting separately.