The Doctrine of Severability or Separability states that when some of the provisions of a statute becomes unconstitutional on account of inconsistency with Fundamental Rights, only the repugnant provision of the law in question shall be treated by the courts as void, and not the whole statute.
Features of the Doctrine of Severability:

• Applicability: Article 13(1) enables High Courts and the Supreme Court to restrain and review any statute enacted by the Legislatures, which contravenes the Fundamental Rights of the people.
• Nature of the disputed provision: The disputed provision shall be proved to be inconsistent with the Fundamental Right in order to hold it to be void. Unless the same is not proven, the said doctrine would not be applicable.
• Severability: When a particular part of a statute bounces beyond the Fundamental Rights, the very part of the statute/Act would be declared void provided that the unconstitutional part of the statute/law is separable. But, if the unconstitutional part of the statute is inseparable, then the entire statute would be held void.
• The burden of the proof: The person who brings the matter to the Court and alleges that the said statute violates the Fundamental Right, it is on her/him to prove that her/his Fundamental Rights have been violated.

Application of Doctrine of Severability in India:

• A.K Gopalan v. State of Madras 1950: The disputed statute here was Preventive Detention Act, 1950 in the light of Article 19 and 21 of the Indian Constitution. The Supreme Court ordered Section 14 of the Act to be severed and held void, while the other provisions remain intact within the statute.
• State of Bombay v. F.N. Balsara – 1951: The disputed statute here was the Bombay Prohibition Act, where the unconstitutional provision was held void and inoperative while the other part of the Act was intact and the statute was still remaining in the force.
• The State of Bombay v. R.M.D. Chamarbaugwala – 1957: The Court applied the Doctrine of Severability in this case and laid down various rules regarding the said doctrine.
• Minerva Mills v. Union of India – 1980: The Supreme Court struck down the Sections 4 & 55 of the 42nd Amendment Act (1976) as it was found ultra vires beyond the amending power of the Parliament. It declared the rest of the Act as valid.\
• Kihoto Hollohan v. Zachillhu – 1992: In this case, the paragraph 7 of the Tenth Schedule, which was first inserted by the 52nd Amendment Act of 1985 was declared as unconstitutional because it had violated the provisions under Article 368(2). But the whole part was not declared unconstitutional.
• Rajendra N. Shah v. Union of India – 2013: The Gujarat High Court ruled the 97th Amendment Act as unconstitutional because inserting Part IX-B without the necessary ratification by states was ultra vires. In a PIL filed against this judgement, the Supreme court declared that the provisions of the Amendment Act with regard to multi state Co-operative societies, will be valid.

The Doctrine of Severability in the Constitution of India is a pre-eminent principle to protect the Fundamental Rights of every citizen of the country. It is an acid test to validate any law that was enacted either in the present Parliament/Legislative Assemblies or in the pre-constitutional period against the Fundamental Rights.