Under which judgment of the Supreme Court, action of the President to summon, prorogue and dissolve either of the Houses of the Parliament shall be unconstitutional, if acted without the advice of Council of Ministers?

The Supreme Court in 'Rao vs. Indira Gandhi (1971)' established that the President's powers to summon, prorogue, or dissolve Houses of Parliament must be exercised on the advice of the Council of Ministers. Acting without such advice would be unconstitutional. This judgment reinforced the constitutional convention of presidential powers being exercised on ministerial advice, making the President a constitutional head.