35.One of the proven methods of examining the legislative competence of a legislature with regard to an enactment is by the application of the doctrine of pith and substance. This doctrine is applied when the legislative competence of the legislature with regard to a particular enactment is challenged with reference to the entries in various lists. If there is a challenge to the legislative competence, the courts will try to ascertain the pith and substance of such enactment on a scrutiny of the Act in question. In this process, it is necessary for the courts to go into and examine the true character of the enactment, its object, its scope and effect to find out whether the enactment in question is genuinely referable to a field of the legislation allotted to the respective legislature under the constitutional scheme. This doctrine is an established principle of law in India recognized not only by this Court, but also by various High Courts. Where a challenge is made to the constitutional validity of a particular State Act with reference to a subject mentioned in any entry in List I, the Court has to look to the substance of the State Act and on such analysis and examination, if it is found that in the pith and substance, it falls under an entry in the State List but there is only an incidental encroachment on any of the matters enumerated in the Union List, the State Act would not become invalid merely because there is incidental encroachment on any of the matters in the Union List.
37.Again, a Constitutional Bench of this Court while discussing the said doctrine in Kartar Singh v. State of Punjab [(1994) 3 SCC 569] observed as under:
"60. This doctrine of `pith and substance' is applied when the legislative competence of a legislature with regard to a particular enactment is challenged with reference to the entries in the various lists i.e. a law dealing with the subject in one list is also touching on a subject in another list. In such a case, what has to be ascertained is the pith and substance of the enactment. On a scrutiny of the Act in question, if found, that the legislation is in substance one on a matter assigned to the legislature enacting that statute, then that Act as a whole must be held to be valid notwithstanding any incidental trenching upon matters beyond its competence i.e. on a matter included in the list belonging to the other legislature. To say differently, incidental encroachment is not altogether forbidden."
39.In Bharat Hydro Power Corpn. Ltd. v. State of Assam [(2004) 2 SCC 553], the doctrine of pith and substance came to be considered, when after referring to a catena of decisions of this Court on the doctrine it was laid down as under: "18. It is likely to happen from time to time that enactment though purporting to deal with a subject in one list touches also on a subject in another list and prima facie looks as if one legislature is impinging on the legislative field of another legislature. This may result in a large number of statutes being declared unconstitutional because the legislature enacting law may appear to have legislated in a field reserved for the other legislature. To examine whether a legislation has impinged on the field of other legislatures, in fact or in substance, or is incidental, keeping in view the true nature of the enactment, the courts have evolved the doctrine of `pith and substance' for the purpose of determining whether it is legislation with respect to matters in one list or the other. Where the question for determination is whether a particular law relates to a particular subject mentioned in one list or the other, the courts look into the substance of the enactment. Thus, if the substance of the enactment falls within the Union List then the incidental encroachment by the enactment on the State List would not make it invalid. This principle came to be established by the Privy Council when it determined appeals from Canada or Australia involving the question of legislative competence of the federation or the States in those countries. This doctrine came to be established in India and derives its genesis from the approach adopted by the courts including the Privy Council in dealing with controversies arising in other federations. For applying the principle of `pith and substance' regard is to be had (i) to the enactment as a whole, (ii) to its main objects, and (iii) to the scope and effect of its provisions. For this see Southern Pharmaceuticals & Chemicals v. State of Kerala [(1981) 4 SCC 391], State of Rajasthan v. G. Chawla [AIR 1959 SC 544], Amar Singhji v. State of Rajasthan [AIR 1955 SC 504], Delhi Cloth and General Mills Co. Ltd. v. Union of India [(1983) 4 SCC 166] and Vijay Kumar Sharma v. State of Karnataka [(1990) 2 SCC 562]. In the last-mentioned case it was held:
41.We find no merit in the contention that the MCOCA, in any way, deals with punishing insurgency directly. We are of the considered view that the legislation only deals with "insurgency" indirectly only to bolster the definition of "organized crime".
42.However, even if it be assumed that "insurgency" has a larger role to play than pointed out by us above in the MCOCA, we are of the considered view that the term "promoting insurgency" as contemplated under Section 2(1)(e) of the MCOCA comes within the concept of public order. From the ratio of the judgments on the point of public order referred to by us earlier, it is clear that anything that affects public peace or tranquility within the State or the Province would also affect public order and the State Legislature is empowered to enact laws aimed at containing or preventing acts which tend to or actually affect public order. Even if the said part of the MCOCA incidentally encroaches upon a field under Entry 1 of the Union list, the same cannot be held to be ultra vires in view of the doctrine of pith and substance as in essence the said part relates to maintenance of Public Order which is essentially a State subject and only incidentally trenches upon a matter falling under the Union List.