“The power of Parliament or for that matter, the State Legislatures is restricted in two ways. A law made by Parliament or the legislature can be struck down by courts on two grounds and two grounds alone, viz., (1) lack of legislative competence and (2) violation of any of the fundamental rights guaranteed in Part III of the Constitution or of any other constitutional provision. There is no third ground………by whatever name it is characterised, the ground of invalidation must fall within the four corners of the two grounds mentioned above. In other words, say, if an enactment is challenged as violative of Article 14, it can be struck down only if it is found that it is violative of the equality clause/equal protection clause enshrined therein. Similarly, if an enactment is challenged as violative of any of the fundamental rights guaranteed by clauses (a) to (g) of Article 19(1), it can be struck down only if it is found not saved by any of the clauses (2) to (6) of Article 19 and so on. No enactment can be struck down by just saying that it is arbitrary or unreasonable. Some or other constitutional infirmity has to be found before invalidating an Act. An enactment cannot be struck down on the ground that court thinks it unjustified. Parliament and the legislatures, composed as they are of the representatives of the people, are supposed to know and be aware of the needs of the people and what is good and bad for them. The court cannot sit in judgment over their wisdom.”
Supreme Court of India
State of A.P. v. McDowell & Co., (1996) 3 SCC 709
“A statutory provision can be struck down on the ground of manifest arbitrariness, when the provision is capricious, irrational and/or without adequate determining principle, as also if it is excessive or disproportionate.”
Supreme Court of India
Shayara Bano v. Union of India, (2017) 9 SCC 1
“Where there is challenge to the constitutional validity of a law enacted by the legislature, the Court must keep in view that there is always a presumption of constitutionality of an enactment, and a clear transgression of constitutional principles must be shown. The fundamental nature and importance of the legislative process needs to be recognised by the Court and due regard and deference must be accorded to the legislative process. Where the legislation is sought to be challenged as being unconstitutional and violative of Article 14 of the Constitution, the Court must remind itself to the principles relating to the applicability of Article 14 in relation to invalidation of legislation. The two dimensions of Article 14 in its application to legislation and rendering legislation invalid are now well recognised and these are: (i) discrimination, based on an impermissible or invalid classification, and (ii) excessive delegation of powers; conferment of uncanalised and unguided powers on the executive, whether in the form of delegated legislation or by way of conferment of authority to pass administrative orders–if such conferment is without any guidance, control or checks, it is violative of Article 14 of the Constitution. The Court also needs to be mindful that a legislation does not become unconstitutional merely because there is another view or because another method may be considered to be as good or even more effective, like any issue of social, or even economic policy. It is well settled that the courts do not substitute their views on what the policy is.”
Supreme Court of India
Subramanian Swamy v. CBI, (2014) 8 SCC 682
“The statute enacted by Parliament or a State Legislature cannot be declared unconstitutional lightly. The court must be able to hold beyond any iota of doubt that the violation of the constitutional provisions was so glaring that the legislative provision under challenge cannot stand. Sans flagrant violation of the constitutional provisions, the law made by Parliament or a State Legislature is not declared bad.”
Supreme Court of India
State of M.P vs Rakesh Kohli & Anr. 2012 (6) SCC 312
“A legislation passed by Parliament can be challenged only on constitutionally recognised grounds. Ordinarily, grounds of attack of a legislation is whether the legislature has legislative competence or whether the legislation is ultra vires the provisions of the Constitution. If any of the provisions of the legislation violates fundamental rights or any other provisions of the Constitution, it could certainly be a valid ground to set aside the legislation by invoking the power of judicial review. A legislation could also be challenged as unreasonable if it violates the principles of equality adumbrated in our Constitution or it unreasonably restricts the fundamental rights under Article 19 of the Constitution. A legislation cannot be challenged simply on the ground of unreasonableness because that by itself does not constitute a ground.”
Supreme Court of India
Ashoka Kumar Thakur vs Union of India (2008) 6 SCC 1 : 3 SCEC 35