Common Cause v. Union of India AIR 2003 SC 4493
Quick answer: what is this case brief about?
The Supreme Court held that no writ of mandamus can be issued to the Central Government to compel the exercise of discretionary power to notify an Act.
[No mandamus for exercise of discretionary power]
ISSUE:
The question whether the Court can issue a mandamus directing the Executive to notify the Act / Amendment or not?
HELD:
In relation to the Delhi Rent Act, 1995, the Supreme Court held that when the legislature itself had vested the power in the Central Government to notify the date from which the Act would come into force, then, the Central Government is entitled to take into consideration various facts while considering when the Act should be brought into force and no mandamus can be issued to the Central Government to issue the notification bringing the Act into force.

