PREM PRAKASH, J. By these petitions under Articles 226 and 227 of the Constitution of India, the petitioners, who are the ten ant of the buildings in question, have challenged the constitutional validity of Explanation (iv) to sub-section (1) of Section 21 of the U. P. Urban Buildings (Regulation of Letting, Rent and Eviction) Act, 1972 (to be hereinafter referred as the Act) and which repealed the U. P. (Temporary) Control of Rent and Eviction Act (described hereinafter as the 1947 Act), on the ground that it violates the funda mental rights of the petitioner, guaranteed under Article 14 and 19 of the Constitution. Counsel for the petitioners conceded and, in our opinion, right ly that since the proclamation of emergency is in operation, under Article 353 of the Constitution, the fundamental right guaranteed under Article 19 is under suspension and, therefore, the explanation could not be assailed for infraction of Article 19. Counsel, however, submitted that it does violate the guarantee of equal protection of the law and offends Article 14 and in his endeavour for attacking the provision as being violative of Article 14 he has maintained that there is a discrimination in favour of the landlord who is in occupa tion of a part of the building for residential purposes and that there is no rational basis for enacting a rule of irrebuttable presumption that the building is bona fide required by him when in other cases the landlord, in order to obtain the eviction of the tenant from the building under tenancy, is required to prove under sub-section (2) (a) of the section that the building is bona fide required by him. In the course of arguments, counsel for the petitioners also raised the con tention, which we permitted them to do, that Rule 16 (1) of the Rules framed under the Act, in so far as it precludes the prescribed autho rity from taking into account the likely hardship to the tenant from the grant of the application in a case covered by Clause (iv) of the explanation, is ultra vires of Section 21 (1) (a) of the Act. Learned Advocate General appearing for the State and the counsel appearing on behalf of the respondents submitted that none of the points urged on behalf of the petitioners has got any substance and there was no violation of the equal protection of laws in Article 14 of the Constitution. For the sake of convenient reference and before we proceed to see the legislative history of the Act, it would be relevant to set out the impugned provision: "21. Proceedings for release of building under occupation of tenant- (1) The prescribed authority may, on an application of the landlord in that behalf, order the eviction of a tenant from the building under tenancy or any specified part thereof if it is satisfied that any of the following grounds exists, namely- (a) that the building is bona fide required either in its exist ing form or after demolition and new construction by the landlord for occupation by himself or any member of his family, or any person for whose benefit it is held by him, either for resi dential purposes or for purposes of any profession, trade or call ing, or where the landlord is the trustee of a public charitable trust, for the objects of the trust; (b) that the building is in dilapidated condition and is re quired for purposes of demolition and new construction. . . . . . " Explanation (iv) to the sub-section reads as thus; (iv) the fact that the building under tenancy is a part of a building, the remaining part thereof is in the occupation of the landlord for residential purposes, shall be conclusive to prove that the building is bona fide required by the landlord. " The 1947 Act imposed several restrictions on eviction of tenants by landlords from buildings, the policy behind it being to alleviate the sufferings of the tenants, if uncontrolled evictions were allowed. Being a measure castled for a limited period, several amendments in response to the needs of the situation were made from time to time and the courts, as well, construed its provisions with the conside ration that it was piece of official legislation meant for the protec tion of tenants. Being a measure castled for a limited period, several amendments in response to the needs of the situation were made from time to time and the courts, as well, construed its provisions with the conside ration that it was piece of official legislation meant for the protec tion of tenants. Amongst the various antinomies pointed out by the Supreme Court in the frame-work of the Act was the one in sub-sec tion (1) of Section 3 which, in the opinion of the Court, did not indi cate the guidelines to regulate the exercise of the power of the Dis trict Magistrate (see Bhagwan Das v. Pram Nath), 1963 A. W. R. 719. The Supreme Court, however, left the question of its validity to be decided to a later occasion. Though there was no express or implied provision in the sub-section requiring the District Magistrate to consider the need of the tenant, the Allahabad High Court, in the light of the decision of the Supreme Court in Laic Shri Bhagwan v. Ram Chandra, 1965 A. L. J. 353 held that while considering the application of the landlord, the Dis trict Magistrate was to give consideration to the cases of both the landlord and the tenant (See Asa Singh v. B. D. Sanwal), A. I. R. 1969 Alld. 474. The economic problem, however, continued unabated owing to the acute scarcity of accommodation and lack of fresh building activity. Some of the provisions of the Act attracted the criticism by informed pub lic opinion and, in that state of facts. The Legislature conscious of the continuing increase in urban population. . . and the problem of shortage of accommodation had become thronic. . . . . . (vide State ments of objects and Reaxons of the Bill) and with a view to provide for the regulation of letting and rent and the eviction of tenants, placed the Act, as a permanent measure, on the Statute Book. The policy underlying the Act manifests that the legislature intended to give greater assurance to tenants against eviction and at the same time it, endeavoring to adapt the conflicting interest of the two segments of the urban population to the social need, placed them upon an ascertainable basis, without leaving such matters to the un bridled discretion of the authorities under the Act. Statutes come out of the past and aim at the future. Statutes come out of the past and aim at the future. This being the background, we would not adopt an interpretation leading to the escalation of mischief to suppress which the legislature has regulated, unless the language is plain and strong enough to warrant that conclusion or unless a breach of the fundamental right of the citizen is mani fest. Since it is apparent that the object of the law, was to afford protection to the tenants from eviction, we would not be doing un due violence to the Act to assume that it was implicitly subject to that condition which alone would make the Act as a whole practicable of administration. In other words, the need of the tenant and the hardship likely to be caused to him by his eviction from the building should also, in absence of the language expressly indicating to the contrary ouster the decision of the prescribed authority. In the aforementioned perspective, we now proceed to have a look at the scheme of Section 21 of the Act, which was two-fold situa tion, (1) a building or any specified part thereof may be released under clause (a) when the prescribed authority is satisfied that such building or part is bona fide required, (i) either in its existing form: or (ii) after demolition and new construction. Such requirement may be for purposes of occupation; (i) by the landlord himself; (ii) in the case of trust, for the objects of the trust. In the first three cases, the building may be released for purposes of residence as well as for purposes of any profession, trade or calling, the landlord thus has not only to prove that there was an element of need and the applica tion was not made with the purpose of rack renting or ejectment with a view to indulge into rack-renting, but he has also to establish that the accommodation was needed for the purpose set out in clause (a ). In other words, it is not enough that the landlord should merely de sire bona fide to use and occupy the premises. What is necessary is that be should need them for his own use and occupation or by any member of his family or by any person for whose benefit the build ing was held by him. In other words, it is not enough that the landlord should merely de sire bona fide to use and occupy the premises. What is necessary is that be should need them for his own use and occupation or by any member of his family or by any person for whose benefit the build ing was held by him. In such an enquiry both sides must adduce relevant evidence before the prescribed authority; the landlord must show that other reasonable accommodation was not available to him and the tenant must also adduce evidence to that effect. It is only after sifting such evidence that the prescribed authority must form its conclusion as to whether much hardship would be caused by re leasing the accommodation then by refusing to release it. (2) The Explanation to the sub-section in the case of a residential building provides in clause (ii) that where the landlord was engaged in any profession, trade, calling or employment, in the city, municipality, notified area or town area within which the building is situate and by reason of the cessation of such engagement he needs the buildings of occupation by himself for residential purposes, such need shall be deemed sufficient for purposes of clause (a) and in a similar way in clause (lii) it indicates that where the landlord is a member of the armed forces of the Union and the prescribed authority under the Indian Soldiers (Litigation) Act, 1925, has issued a certificate in his favour that he is serving under special conditions within the meaning of Section 3 of the Act, then his representation that he needs the building for residential purposes for members of his family shall be deemed sufficient for purposes of clause (a ). In these two classes of cases the landlords need has been declared as sufficient relieving the landlord of the obligation to prove it by evidence as has been re quired by sub-section (1) (a ). In these two classes of cases the landlords need has been declared as sufficient relieving the landlord of the obligation to prove it by evidence as has been re quired by sub-section (1) (a ). On the other hand, if, as one must take for granted, clause (iv) of the explanation precludes a tenant from questioning the existence of the bona fide requirement of the landlord in respect of an appli cation for release, a fortiorari must have to be inferred from its lan guage and the setting in which it occurs that the Legislature did not wish that the landlord was relieved of the necessity to prove that the building was required for the purposes specified in clause (a ). Judg ing the matter with reference to the preceding clauses of the Expla nation and the requirements of clause (a) of sub-section (1) we are compelled to conclude that the irrebuttabie presumption regarding the existence of the bona fide requirement of the landlord does not shut out an enquiry by the prescribed authority as to the need of the landlord. Whether or not there is a bona fide requirement is merely a preliminary proceeding and, in our opinion, can result in no final judgment against the tenant except as the consequence of an enquiry in which the tenant and the landlord alike would have the opportunity of being heard inasmuch as in such an enquiry the pres cribed authority would have to weigh the real need of the landlord with the inconvenience that the tenant will suffer by effect of a re lease order. The history of the legislation and the scheme of the Explanation should, in our opinion, preclude a conclusion to the contrary. Having regard to the scheme of the Explanation, and the fact that it does not bar an enquiry in essential matter relevant to the determination of the lis between the parties we are unable to sustain the contention that the irrebuttabie presumption contained in Clause (iv) of the Explanation is either unreasonable or inhibits the gua rantee of equal protection of law. The State possesses the general power to prescribe the evidence which shall be received and the effect which shall be given to it in its courts and may exercise this power by providing that proof of a particular fact or of several taken collectively shall be prima facie or conclusive evidence of another fact. Many such exercise of this power are shown in the various legislations and for our present purposes it is sufficient to mention that the Evidence Act is full of such fictions. In exercise of the po wer, the Legislature cannot only act on irrebuttabie presumptions which may also form part of substantive law (vide Izhar Ahmed Khan v. Union of India, A. I. R. 1962 S. C. 1052. The provision of law, which shuts out further enquiry and makes a certain fact conclusive upon the proof of some other fact, does not involve the exercise of any judicial function. The law of evidence is full of fic tions which also involves proof of facts. It has never been suggested before that when a Legislature says that in an enquiry the truth or otherwise of a fact shall stop at a given stage and that fact is taken to be conclusively proved, that a question of discrimination arises (See Municipal. Board,. Hapur v. Raghuvendra Kripal, A. I. R. 1966 S. C. 693 and, as held by the Supreme Court in their recent decision in Mahant Dhram Das v. State of Punjab, Civil Appeals Nos. 354, 122 and 19651 of 1cg9 decided January 14, 1975 (S. C.) such irrebuttabie and conclusive presumption not only as mere rules of evidence but as substantive piece of law, the Legislature is competent to provide so long as the relevant provisions are within the legislative competence of the Legislature and are not otherwise unconstitutional. The validity of such statutory presumption was brought in ques tion before the American Supreme Court in Noble J. and K. C. R. Co. v. Trupinseed, 219 U. S. 35, 43 and it was said there that a Legislative presump tion of one fact. . . . . . . The validity of such statutory presumption was brought in ques tion before the American Supreme Court in Noble J. and K. C. R. Co. v. Trupinseed, 219 U. S. 35, 43 and it was said there that a Legislative presump tion of one fact. . . . . . . from evidence of another may not constitute a denial of due process of law or a denial of the equal protection of the law, it is only essential that there shall be some rational connection between the fact proved and the ultimate fact presumed, and that the inference of one fact from proof of another shall not be unreasonable as to be a purely arbitrary mandate. So, also, it must not, under guise of regulating the presentation of evidence operate to preclude the party from the right to present his defence to the main fact thus pre sumed. If a legislative provision not unreasonable in itself, prescrib ing a rule of evidence, in either criminal or civil cases, does not shut out from the party affected a reasonable opportunity to sub mit to the injury in his defence all of the facts bearing upon the issue, there is no ground for holding that due process of law has been denied to him. however unjust and oppressive a provision it might be or, as Cooley, in a Treatise on the Constitutional Limitations at page 164 puts it, "it is supposed to violate the natural, social, or political right of the citizen, it cannot be declared unconstitutional unless it can be shown that such injustice is prohibited or such rights are guaranteed or protected by the Constitution. " In a similar strain, though in a different language, Willoughby has summed up the position in his book. The Constitutional Laws of the United States, Second Edition, Vol. Ill, at page 1820, in these words. the flexibility for capacity for growth and adoption is the peculiary boast of excellence of the common law. The general doc trine then is that so long as existing vested property rights are not dis turbed, the substantive law, whether of common law or of statutory creation, is subject to change. That is, a change in the substantive Jaw is not per se a deprivation of the rights of life, liberty and pro perty of the individuals affected by it. . That is, a change in the substantive Jaw is not per se a deprivation of the rights of life, liberty and pro perty of the individuals affected by it. . Rights of property which have been created on the common law cannot be taken away without due process but the law itself, as a rule of conduct, may be changed at the will, or even the whim, of the legislature. The impugned provision, in the light of the principle laid down in Izhar Ahmads case (Supra), is, in our opinion, a rule of evidence because the fact that the landlord is in residential occupation of a part of the accommodation bears a probative or a persuasive value in the matter of proving the existence of bona fide requirement. There is a rational connection between the landlord being in occupation of a part of the accommodation and the ultimate fact presumed, name ly, that because of his living in a part of the accommodation he bona field requires the accommodation. It is common knowledge that the need of a landlord in occupation of part of residential building should, in the normal course of events, be genuine and if the legis lature on the basis of experience and appreciating the need of its own people presumed the existence of the bona fide requirement, the rule so prescribed cannot be held to be arbitrary. Though the sec tion does not shed much light, but we may conceive that the inten tion of the Legislature in putting the existence of bona fide requirement beyond the region of controversy was to reduce the area of con flict and minimize the extent of litigation between the landlord and the tenant. Some hardship in stray cases is bound to occur, but that cannot move the court in upsetting the legislative discretion. In de termining the Constitutionality of the statute we should construe it in such a manner as to sustain it and every possible presumption will be indulged in for that purpose. The Legislature in its wisdom has made the presumption conclusive and it is not for the court to ques tion that wisdom. Nor does the irrefutable presumption oust the right of the tenant to present his defence in full, in the list between, him and the landlord. The Legislature in its wisdom has made the presumption conclusive and it is not for the court to ques tion that wisdom. Nor does the irrefutable presumption oust the right of the tenant to present his defence in full, in the list between, him and the landlord. Indeed the substance of the original justice has been maintained and it is not possible to hold that the tenant has been deprived of his statutory right. In the enquiry before the pres cribed authority each party, as we have analysed in the foregoing, would have an opportunity to give evidence to show that hardship would be caused to him by the granting or refusal of the application and it will be for the prescribed authority to determine whether the suffering of the tenant, in case a release order was made, would be more than that of the landlord by its refusal. For these considera tions, we find ourselves unable to sustain the petitioners contention that clause (iv) of the Explanation to sub-section (1) of Section 21 of the Act, which is in the nature of a rule of evidence, suffers from the vice of unconstitutionally. But the challenge that Rule 16 (1) of the Rules framed under the Act is ultra vires of Section 21, to the extent it takes out from the ambit cases falling within Explanation (iv) of Section 21, must suc ceed. The Rule provides that in considering the requirements of personal occupation for purposes of residence of the landlord or any member of his family, the prescribe authority shall, except in cases provided for in the Explanation to Section 21 (1), take into account the likely hardship to the tenant from the grant of the application as against the likely hardship to the landlord from the refusal of the application. The Rule also lays down the considerations which may weigh with the prescribed authority in arriving at a decision. In the above we have shown that even in cases, to which Explanation (iv) is applicable, the objects of the Act and the Scheme of Section 21 contemplate enquiry, as aforesaid. The law is well settled that the rules being ancillary and subservient to the enactment cannot go against its provisions and cannot in any manner make any change in the provision of the enactment. The law is well settled that the rules being ancillary and subservient to the enactment cannot go against its provisions and cannot in any manner make any change in the provision of the enactment. They are merely for the purpose of carrying out the essential policy which the Legislature as laid, down in the enactment itself (see Arnold Rodricks v. State of Maharashtra, A. I. R. 1966 S. C. 1788 at p. 1803. The conclusion is inescapable that the Rule in so far it precludes the enquiry, in cases covered by Clause (iv) of the Explanation, is not in accord with the principles and consequently it should be struck down to that extent as being ultra vires of the power conferred on the State Government, and we hold accordingly. Having disposed of the points, which in common were raised by the petitioners, we turn to the petitions separately to examine whether the impugned orders require our interference. Writ Petitions Nos. 224 and 319 disclose a similar situation. The landlord, allegedly living in a portion of the accommodation, made an application under Section 21 (1) (a) read with Explanation (iv) of the Act for the eviction of the petitioner on the ground that he needed the accommoda tion for his use. The tenant soon after the service of the notice of the application and without waiting for the decision by the prescribed authority, rushed to the Court praying for the issue of a writ or direction, declaring Clause (iv) of the Explanation to Section 21 (1)as M-A. LL. B unconstitutional, and for other relief, if any. But, in our the extraordinary remedy sought by the petitioner is premature. The prescribed authority possesses the jurisdiction to entertain and de cide an application for release under Section 21 (1) (a) of the Act, a writ of prohibition or a direction in that nature may not be used to usurp or perform the functions of an appeal or a writ of certiorari when the general scope and purpose of the action is within the juris diction of the inferior tribunal. The prescribed authority on a con sideration of the evidence adduced before him may or may not ac cept the contention of the landlord and if the order of the prescribed authority went against the petitioner, the latter has got an adequate and efficacious remedy under Section 22 by way of appeal to take District Judge. This disposes of Writ Petitions Nos. 224 and 319 of 1973. In Writ Petitions Nos. 763 of 1974 and 1047 of 1974 the order passed by the District Judge under Section 22 of the Act seems to suffer from a legal infirmity in that the court in making order of re lease, in disagreement with the prescribed authority, has not balanc ed the need of the landlord with the hardship likely to be caused to the tenant, in case his eviction was allowed. In one case the land lord is in occupation of the first floor of the house and the ground floor has been in the occupation of the tenant from the year 1961. The prescribed authority upon an appraisal of the conclusion that they were two separate accommodation and that the landlord was unable to prove his need. The Addl. District Judge, without entering into the Question of need and taking the view that when once it was held that Explanation (iv) was applicable, the prescribed authority was bound to pass an order of eviction of the tenant, has released the accommodation. And, in another case (Writ Petition No. 1047 of 1p74") the petitioner was tenant of a room in the ground-floor where he had been running his Aushdhalaya. The prescribed authority negative the contention of the landlord, but the Addl. District Judge, and lying Explanation Civil and without entering into the question of need of the landlord and the hardship likely to be caused to be tenant by his eviction made an order of release. In view of what we have said about the scone of Section 21 (1) (a) of the Act, the order of the Addl. District Judge, suffers from a jurisdictional error and it deserve to be quashed. In view of what we have said about the scone of Section 21 (1) (a) of the Act, the order of the Addl. District Judge, suffers from a jurisdictional error and it deserve to be quashed. For the discussion in the above, we maintain the constitutional ity of Explanation (iv) to Section 21 (1) (a) of the Act, the order of the Rules, framed under the Act, to the extent it excludes from its application cases covered by clause (iv) of the Explanation, on the ground of it being ultra vires of the Act. Writ Petitions Nos. 224 of 1973 and 319 of 1973 are dismissed with costs. The stay order is vacated. Writ Petitions Nos. 763 of 1974 and 1047 of 1974 succeed and the Rule is made absolute. Annexure 3 (in writ Petition No. 763 of 30 1974) is quashed The District Judge is directed to re-hear the ap peals in the light of the observations made in the above after affording full opportunity of hearing to the parties on the evidence already available on the record. An appropriate writ or direction may issue in that behalf. The petitioner will recover his costs from opposite party No. 1. .