Which of the following statements is/are correct about National Emergency?

1. It can be imposed before the actual occurrence of war or any such aggression or rebellion if the President is satisfied that there is imminent danger thereof.

2. It is imposed four times.

3. President can only issue such a declaration after receiving a decision from Union Cabinet in writing.

4. Article 19 is automatically suspended when the National Emergency is imposed in case of the proclamation on the ground of war or external aggression.