JUDGMENT Sengupta, J. : By this application the judgment and order of the West Bengal Taxation Tribunal dated 14th January, 2005 has been impugned. The learned Tribunal by the impugned judgment and order has disposed of a batch of applications numbering 141. In those batch of matters it appears that the vires of the amendment of Section 39 made by inserting sub-section 4 along with explanation was challenged. The. challenge before the learned Tribunal failed. 2. The short facts culminating before this Court are as follows: – The petitioner is a manufacturer of spices. At the material point of time the petitioner was a newly set up small scale industrial unit and its first sale from such unit was made on 10th June, 2002. The industrial unit of the petitioner is situated in North 24 Parganas within the area where the benefit of tax holiday for seven years had been allowed under Section 39 of the West Bengal Sales Tax Act, 1994. The petitioner claims that it is entitled to this benefit of tax holiday for a period of 7 years prior to amendment. Accordingly, the petitioner was granted eligibility certificate on and from 17th July, 2002. The eligibility certificate was issued to the petitioner on 30th of May, 2003 mentioning the validity period from 10th June, 2002 to 9th June, 2009. Before the certificate was issued to the petitioner, as aforesaid, Section 30 with insertion of sub-section 4, was amended with effect from 1st April, 2003. According to proviso to the said sub-section, a newly set up small scale industrial unit is entitled to enjoy tax holiday to the maximum of 200 per cent of the gross value of the fixed asset. The gross value of fixed asset was defined in explanation to subsection 4 of Section 39. Hence, applying the aforesaid amended law and endorsement was subject to 200 per cent of GVFCA for the period from 10th June, 2002 to 9th June, 2009. 3. It is submitted that learned Tribunal was in error not upholding the challenge to the said sub-section on the ground of constitutional invalidity. 4. Smt. Chandrima Bhattachaiya, learned Counsel appearing for the petitioner submits that when the application was made the unamended Section 39 was in operation and while granting the certificate the amended law cannot be pressed into operation. It is submitted that learned Tribunal was in error not upholding the challenge to the said sub-section on the ground of constitutional invalidity. 4. Smt. Chandrima Bhattachaiya, learned Counsel appearing for the petitioner submits that when the application was made the unamended Section 39 was in operation and while granting the certificate the amended law cannot be pressed into operation. Such an action aiming at to give retrospective effect to the amended law is unreasonable and violative of Article 14 of the Constitution of India. 5. She submits that acting upon the unamended provision of Section 39 her clients had made investment and certificate had been issued to give benefit from the date of first sale i.e., 10th June, 2002 till 9th June, 2009. The petitioner made all investments and altered its position going by legal provision, the State is estopped from denying the benefit giving retrospective effect which is not at all contemplated therein. That apart the petitioner relying on a Single Bench decision of this Court contends that the State is estopped from taking away such benefit after holding out a promise under Section 39 for giving such benefit, by amending the said provision subsequently intending to take away such benefit. Hence, her client is entitled to get the benefit for full 7 years of tax holiday as the petitioner restricted its investment to Rs. 35 lakh on the plant and machinery. She has relied on judgment of learned Single Judge of this Court reported' in (2007) 5 VST 92 (Cal), unreported one of the Division Bench of this Court in the case of Pacific Health Care Private Limited v. State of West Bengal and Others and the Supreme Court's decision reported in (1996) 3 SCC 709 (State of A.P. and others v. Mac Dowell and Company and Ors.). 6. Mr. Abhratosh Majumdar, learned Counsel while countering the submission of the petitioner firstly contends that the petitioner cannot get any benefit of tax holidays at all as when the certificate was issued factually the benefit had been withdrawn. 7. 6. Mr. Abhratosh Majumdar, learned Counsel while countering the submission of the petitioner firstly contends that the petitioner cannot get any benefit of tax holidays at all as when the certificate was issued factually the benefit had been withdrawn. 7. He submits while relying on a Single Bench decision of this Court in case of Hindustan Lever Limited and Others v. State of West Bengal and Another reported in 5 VST 92 and also the Supreme Court judgment in Mac Dowell case that the promissory estoppel cannot be invoked as against legislative action as amendment has been made by State Legislature. It is not a case that the State Legislature is incompetent to make amendment with insertion of sub-section 4 in Section 39. Restriction on the quantum of investment under Rule 98 had not been challenged by the petitioner. In the present case the benefit has not been withdrawn in the midway therefore by any stretch of imagination promissory estoppel cannot be applied. 8. Having heard the learned Counsel for the parties and having gone through the judgment of the learned Tribunal we think that there is no dispute as regard legislative competence to amend the existing law. Hence this Court is called upon to examine whether on the ground of unreasonableness or for that matter on the anvil of Article 14 of the Constitution of India amendment can be held to be unconstitutional on the facts and circumstances of this case or not. While examining this aspect of the matter allegation of unreasonableness has to be established by cogent materials by the person who asserts so. Whenever any enactment is made by the appropriate legislature constitutional validity which includes the reasonableness and absence of arbitrariness is always presumed and this presumption has to be rebutted by the litigant who seeks to challenge legislative action. The petitioner is seeking to assert that promise held out by statutory provision, is sought to be taken away thus it is an unreasonable. We are unable to accept this plea as benefit which was sought to be given is a concession and it cannot be claimed as a matter of right, as such plea of affectation of right does not" arise. Therefore element of arbitrariness in this amendment is absolutely missing. We are unable to accept this plea as benefit which was sought to be given is a concession and it cannot be claimed as a matter of right, as such plea of affectation of right does not" arise. Therefore element of arbitrariness in this amendment is absolutely missing. In the case of Mac Dowell reported in (1996) 3 SCC page 709 the observation of the Supreme Court has clearly laid down the parameter to accept challenge to the legislative action. In paragraph 43 it is observed as follows : – "................It is enough for us to say that 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 arbitray 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.” 9. In this case when the legislature having felt the need of the situation and decided to amend the concessional provision of law, the Court cannot on mere allegation of arbitrariness strike down as there has been no affectation of the right of the petitioner which existed before withdrawing concession under the provision of law. 10. In this case when the legislature having felt the need of the situation and decided to amend the concessional provision of law, the Court cannot on mere allegation of arbitrariness strike down as there has been no affectation of the right of the petitioner which existed before withdrawing concession under the provision of law. 10. The learned Single Judge of this Court in case of Hindustan Lever Ltd. and Another v. State of West Bengal and Others reported in (2007) 5 VST 92 (Cal), while surveying large number of Supreme Court decisions on this subject : "Upon careful reading of all these decisions it appears to me the principle uniformly laid down by the Supreme Court for enforcement of promissory estoppel is that the State is bound by the promise if the promise altered its position by acting upon." 11. In this decision the learned Single Judge has made a distinction as to applicability of the promissory estoppel. It was held in that case that in case of executive action in some cases the promissory estoppel could be applied to but not in case of legislative action. 12. The unreported decision relied on by Smt. Bhattacharya, inter alia held that if amended provision of law was given retrospective operation in the matter of sales tax wherein any benefit given to a dealer is withdrawn with retrospective effect the same will obviously operate as an oppressive, arbitrary and unconstitutional measure. The said decision however, accepted the legislative competence of the prospective operation. It was found on fact in that case the retrospective operation of the amended provision of the Act will act harshly and public at large will be not affected if prospective operation is given because the result of retrospective operation would amount to irreparable loss for acting upon the concessional benefit. The dealer did not realise any sales tax and it would be impossible to collect the sales tax which were not collected acting upon such provision of law as the sales tax being indirectly imposed the same is not payable by the dealer. Therefore, as rightly pointed out by Mr. Majumdar the said decision is distinguishable on fact. Accepting the argument of Mr. Majumdar we hold that the amendment is not ultra vires and, thus, affirm the judgment of the learned Tribunal. Therefore, as rightly pointed out by Mr. Majumdar the said decision is distinguishable on fact. Accepting the argument of Mr. Majumdar we hold that the amendment is not ultra vires and, thus, affirm the judgment of the learned Tribunal. At the same time we also hold that this amendment has not been given any retrospective operation as it has got prospective operation. We, therefore, think it fit that petitioner in this case will get benefit of the concession under the unamended portion for the period from first sale i.e., 10th June, 2002 till the date of the said amendment as per the eligibility certificate and the petitioner will not get any benefit for the rest of, the period i.e., from 1st April, 2003 till the next and petitioner will get benefit if entitled under the amended provision for this period. This application is thus allowed to the extent as above. Bagchi, J. : I agree.