Explanation: Under Article 352, the President can declare a national emergency when the security of India or a part of it is threatened by war or external aggression or armed rebellion. It may be noted that the president can declare a national emergency even before the actual occurrence of war or external aggression or armed rebellion, if he is satisfied that there is an imminent danger.

The President can also issue different proclamations on grounds of war, external aggression, armed rebellion, or imminent danger thereof, whether there is a proclamation already issued by him and such proclamation is in operation. This provision was added by the 38th Amendment Act of 1975.

Source: Indian Polity Laxmikanth