Basic structure doctrine

The primary test for constitutionality under the precedents of the Supreme Court of India is a test for whether the 'Basic Structure' of the Constitution has been in any way modified by the Act under consideration.

On April 24, 1973, the Supreme Court ruled in Keshavananda Bharati v. the State of Kerala that although the 25th Amendment of 1971 was constitutional, the court still reserved for itself the discretion to reject any constitutional amendments passed by Parliament by declaring that the amendments cannot change the constitution's "basic structure". This doctrine was applied famously to the 39th Amendment of 1975, which attempted, among other provisions, to pass legislative judgment over the election of Indira Gandhi in 1971.

The doctrine was expanded in the Minerva Mills case of 1981.