Question

when is the President's rule imposed in a state​

Answer 1

Answer:

when CM of the state does not work properly and done the work against the constitution or the system of the state does not work in his duty in that case the Governor of the state suggest to the President of the nation to rule the state by himself.

It term called President's Rule.

Answer 2

Answer:

Article 356 state that the president can invoke president rule in a state on the report of the governor if the state machinery/legislature fails to abide by constitutional norms.