Answer:

National emergency under article 352 can be proclaimed when the security of India or a part of it is threatened by war, external aggression or armed rebellion. President’s rule is an emergency declared under article 356 due to the failure of the constitutional machinery in the states. It can be proclaimed when the government of a state cannot be carried on in accordance with the provisions of the Constitution due to reasons which may not have any connection with war, external aggression or armed rebellion.

Effects on Fundamental rights

When a proclamation of national emergency is made, the six fundamental Rights under article 19 are automatically suspended on the ground of war or external aggression. The president can also suspend the right to move any court for the enforcement of Fundamental Rights during a National Emergency except for article 20 and 21. Also, only those laws which are related with the emergency are protected from being challenged and not the other laws. Also, the executive action taken only under such a law is protected.

President's rule, on the other hand, has no effect on Fundamental Rights of the citizens.