ORDER Sri Ramesh Ranganathan, J. The petitioner, a small scale industrial unit engaged in the business of production of oxygen gas and effecting sales thereof duly filling it in cylinders, obtained the final eligibility certificate, under G.O.Ms. No. 108 dated 20.05.1996, on 15.06.1999. The said certificate entitled the petitioner to claim the benefit of sales tax holiday for Rs. 1,33,73,140/- for a period of seven years from 11.02.1999 till 10.02.2006, apart from other incentives. Clause 11(vi) thereof disentitled the petitioner from collecting sales tax from its consumers and required it, in case it collected sales tax during the availed period of sales tax exemption, to remit the sales tax collected by it to the government. Placing reliance on the circular memo issued by the Commissioner of Industries dated 17.05.2000, purporting to withdraw the tax holiday for industrial gases etc., the 1st respondent issued show cause notice dated 29.07.2000 proposing to assess the petitioner herein. Challenging the jurisdiction of the 1st respondent to levy sales tax, the petitioner filed W.P. No. 22175 of 2000 requesting this Court to set aside the Circular memo dated 17.05.2000 and to direct the authorities to extend the benefit of tax holiday under the Target - 2000 scheme. The said writ petition was admitted on 17.11.2000 and an interim order was passed directing the respondents not to withdraw the benefit extended to the petitioner under the final eligibility certificate dated 15.06.1999. Thereafter, the General Manager, District Industries Centre, Medak issued proceedings dated 12.01.2001 cancelling the final eligibility certificate dated 15.06.1999 aggrieved by which the petitioner filed W.P. No. 19631 of 2001. The said writ petition was allowed by order dated 20.09.2001 on the ground that the General Manager had no jurisdiction to cancel the final eligibility certificate. In the meanwhile, the 1st respondent - Commercial Tax Officer finalized the assessment for the years 2000-01, 2001-02 and 2002-03 by orders dated 18.12.2003, 05.03.2005 and 16.11.2005 respectively. A Full Bench of this Court, in Panchalingala Carbonic Gas Pvt. Ltd. v. State of A.P. (Vol. In the meanwhile, the 1st respondent - Commercial Tax Officer finalized the assessment for the years 2000-01, 2001-02 and 2002-03 by orders dated 18.12.2003, 05.03.2005 and 16.11.2005 respectively. A Full Bench of this Court, in Panchalingala Carbonic Gas Pvt. Ltd. v. State of A.P. (Vol. 40 APSTJ 41) (Judgment in W.P. No. 22680/2000 and W.P. 13306/04 dated 26.11.2004), held that the activity of the assessee's unit in converting oxygen/carbon dioxide from liquid form into gaseous form did not involve a process of manufacture irrespective of the difference as to the form in which it was purchased by the industry and the form in which the same was supplied to its customers, that the incentive of tax holiday on sales tax under G.O.Ms. No. 108 dated 20.05.1996 was available only to those industries where a process of manufacture took place subject to their not having been excluded under the annexure, that the liability to pay tax, arising out of cancellation of incentives, would start from the date on which the orders become operative, that, in view of Clause (vi) of the final eligibility certificate, small scale industrial units were not only disabled but, in fact, were prohibited from collecting tax, that it was impermissible to compel them to pay tax which they did not collect and that it was open to the Government to recover tax from such units if it was found that they had collected sales tax on such product during the subsistence of the incentives. Following the Full Bench Judgment in Panchalingala Carbonic Gas Pvt. Ltd. (Vol. 40 APSTJ 41), a Division Bench of this Court, in W.P. No. 22175 of 2000, passed the following order on 02.09.2005 :- "The subject-matter that arises for consideration in this writ petition is squarely covered by an authoritative pronouncement of this Court in Panchalingala Carbonic Gas Private Limited, Kurnool v. State of A.P. ( 2005 (1) ALD 225 (FB)). Following the said judgment, this writ petition shall stand dismissed without any order as to costs." As neither of the parties have chosen to prefer an appeal thereagainst the order of the Division Bench, in W.P. No. 22175 of 2000 dated 02.09.1995, attained finality. Following the said judgment, this writ petition shall stand dismissed without any order as to costs." As neither of the parties have chosen to prefer an appeal thereagainst the order of the Division Bench, in W.P. No. 22175 of 2000 dated 02.09.1995, attained finality. The 1st respondent issued garnishee notice dated 28.06.2007 to Punjab National Bank, Patancheru branch for recovery of tax arrears due for the assessment years 2000-01, 2001-02 and 2002-03 though the petitioners did not have any account in said bank. The petitioner submitted a representation on 13.07.2007 requesting that no coercive steps be taken. The 1st respondent issued another notice dated 22.08.2008 demanding payment of arrears of Rs. 31,62,880/- for the assessment years 2000-01, 2001-02 and 2002-03 and, thereafter, issued garnishee notice dated 06.09.2008 to the petitioner's banker i.e., the 2nd respondent. Petitioner would contend that the 1st respondent had no jurisdiction to recover sales tax as they had not collected the same and, as there was no dispute as to the quantification of the turnover or the sales tax component, there was no necessity or warrant for filing an appeal, that it is a small scale industry running on a shoe string budget, that it has not collected tax in view of the condition imposed in the final eligibility certificate dated 15.06.1999, that they should not be mulcted with such a huge liability and that, if they were forced to pay the disputed tax, they would be out of business. In his counter-affidavit, the 1st respondent admits that the petitioner was issued final eligibility certificate dated 15.06.1999 and, thereunder, they were entitled to sales tax holiday for Rs. 1,33,73,140/- for a period of seven years from 11.02.1999 to 10.02.2006. The facts stated in the affidavit filed in support of the writ petition are not denied. It is, however, contended that the petitioner was wrongly given incentives and benefits contrary to the law laid down by this Court in Panchalingala (Vol. 40 APSTJ 41), that the order granting incentives was passed in illegal exercise of jurisdiction and that, in K. Premerajan v. State of Kerala (Vol. It is, however, contended that the petitioner was wrongly given incentives and benefits contrary to the law laid down by this Court in Panchalingala (Vol. 40 APSTJ 41), that the order granting incentives was passed in illegal exercise of jurisdiction and that, in K. Premerajan v. State of Kerala (Vol. 14 VST 202), the Kerala High Court had held that, when an order was passed without authority of law and without jurisdiction, it was non-est and the assessing authority was not bound to give effect to it while computing the assessments and, therefore, he had passed assessment orders for the three assessment years levying tax of Rs. 31,62,880/-. The 1st respondent would state that the assessment order had become final as no appeals were preferred thereagainst and since, despite repeated demands, the petitioner did not clear the dues, he was constrained to issue the impugned notice to recover the tax legitimately due to the revenue. The 1st respondent would contend that, as the assessee was liable to pay sales tax, the question whether they had collected tax from their customers or not was of no consequence and that the petitioner, being an assessee, had to clear their tax dues. What was under challenge in the writ petition was only the garnishee notices dated 06.09.2008 and 22.08.2008 and not the assessment orders for the three years 2000-01 to 2002-03. Sri S. R. Ashok, Learned Senior Counsel for the petitioner, would contend that, as the assessment orders were passed during the period when the interim order passed in W.P. No. 22175 of 2000 was in force and as the Commercial Tax Officer was a party to the said writ petition, the assessment orders passed by him were a nullity and were required to be declared as such. It is well settled that all decisions are presumed to be valid until set aside or otherwise held to be invalid by a court of competent jurisdiction. (Judicial Review of Administrative Action, De Smith, Woolf and Jowell, 1995 Edn., at pp. 259-60). Until its validity is challenged, its legality is preserved. (Halsbury's Laws of England, 4th Edn., (Re-issue) Vol. 1(1) in para 26, p. 31). An order, even if not made in good faith, is still an act capable of legal consequences. It bears no brand of invalidity on its forehead. 259-60). Until its validity is challenged, its legality is preserved. (Halsbury's Laws of England, 4th Edn., (Re-issue) Vol. 1(1) in para 26, p. 31). An order, even if not made in good faith, is still an act capable of legal consequences. It bears no brand of invalidity on its forehead. Unless the necessary proceedings are taken at law to establish the cause of invalidity, and to get it quashed or otherwise upset, it will remain as effective for its ostensible purpose as the most impeccable of orders. This is equally true even where the brand of invalidity is plainly visible for there also the order can effectively be resisted in law only by obtaining the decision of the court. (Wade and Forsyth : Administrative Law, Seventh Edn., at pp. 341-342; Smith v. East Elloe Rural District Council (1956 AC 736)). It will be a dangerous proposition to be laid down as one of law that any individual or authority can ignore the order assuming authority upon itself to decide that the order is coram non judice. A judicial/quasi-judicial order, not invalid on its face, must be given effect to entailing all consequences, till it is declared void in a duly constituted judicial proceedings. (Prakash Narain Sharma v. Burmah Shell Coop. Housing Society Ltd. ( (2002) 7 SCC 46 )). If an act is void or ultra vires it is enough for the court to declare it so and it collapses automatically. It need not be set aside. The aggrieved party can simply seek a declaration that it is void and not binding upon him. But, nonetheless, the order has at least a de facto operation unless and until it is declared to be void or a nullity by a court. A party aggrieved by the invalidity of the order has to approach the court for the relief of declaration that the order against him is inoperative and not binding upon him. (State of Punjab v. Gurdev Singh ( (1991) 4 SCC 1 )). The order may be hypothetically a nullity, but the court may refuse to quash it because of some legal reason. In any such case the 'void' order remains effective and is, in reality, valid. (Wade : Administrative Law 6th edition Page 352). (State of Punjab v. Gurdev Singh ( (1991) 4 SCC 1 )). The order may be hypothetically a nullity, but the court may refuse to quash it because of some legal reason. In any such case the 'void' order remains effective and is, in reality, valid. (Wade : Administrative Law 6th edition Page 352). On being asked whether the assessment orders could be set aside, even in the absence of a challenge thereto, Learned Senior counsel sought time to have a petition filed seeking amendment of the prayer. Thereafter, W.P.M.P. No. 843 of 2009 was filed to amend the prayer in the writ petition and a declaration is now sought that the assessment orders for the three years 2000-01, 2001-02 and 2002-03, being in violation of the interim order dated 17.11.2000 in W.P.M.P. No. 28204 of 2000 and final order dated 02.09.2005 in W.P. No. 22175/2000, was void and non-est, that it was required to be set aside and that the respondent be interdicted from recovering the tax payable under the assessment orders for the three years. The matter was adjourned to enable the learned Government Pleader to obtain instructions in this W.P.M.P. At the request of both the counsel, the writ petition and the W.P.M.P were taken up for final hearing on 29.01.2009 and are now being disposed of by this order. As noted hereinabove, withdrawal of tax holiday for units manufacturing industrial gases, vide circular of the Commissioner of Industries dated 17.05.2000, was under challenge in W.P. No. 22175 of 2000 wherein the 1st respondent herein was the 3rd respondent. This Court passed an interim order dated 17.11.2000 directing the respondents not to withdraw the final eligibility certificate dated 15.06.1999 whereunder the petitioner was entitled for sales tax holiday for a period of seven years and was prohibited from collecting sales tax from its consumers during this period. The interim order passed by this Court continued to remain in force till W.P. No. 22175 of 2000 was finally decided by order dated 02.09.2005 following the judgment of the Full Bench in Panchalingala Carbonic Gas Private Limited (Vol. 40 APSTJ 41). It was during the period when the interim order was in force, that the assessment orders for the years 2000-01 and 2001-02 were passed on 18.12.2003 and 05.03.2005, in effect, setting at naught the interim order passed by this court. 40 APSTJ 41). It was during the period when the interim order was in force, that the assessment orders for the years 2000-01 and 2001-02 were passed on 18.12.2003 and 05.03.2005, in effect, setting at naught the interim order passed by this court. As he was a party to W.P. No. 22175 of 2000, it was not open to the 1st respondent herein to act contrary to the interim order passed by this Court on 17.11.2000. It is settled law that an order passed by a Court, more so, a superior court, even it be interim in nature, is binding till it is set aside and it cannot be ignored. (Ravi S. Naik v. Union of India (1994 Supp. (2) SCC 641)). The assessment order for the year 2002-03 was passed on 16.11.2005 after final orders were passed in W.P. No. 22175 of 2000 dated 02.09.2005 following the judgment in Panchalingala Carbonic Gas Pvt. Ltd. (Vol. 40 APSTJ 41), wherein the Full Bench held that it was only in cases where the assessee - units had collected sales tax from its consumers was it open to the government to recover the sales tax collected by them. The assessment orders passed by the 1st respondent fall foul of both the interim order and the final order of this Court in W.P. No. 22175 of 2000. The 1st respondent, being a party to W.P. No. 22175 of 2000, could not have acted contrary thereto. While it is true that an assessee is liable to pay sales tax and the question whether he had collected tax from his consumers is of no consequence, (American Remedies Pvt. Ltd. v. Govt. of A.P. ( (1999) 113 STC 400 ); K. Premerajan (Vol. 14 VST 202)), it must also be borne in mind that a judgment of the High Court under Article 226, passed after a hearing on merits, must bind the parties till set aside in appeal. (Direct Recruit Class II Engineering Officers' Association vs. State of Maharashtra ( (1990) 2 SCC 715 ); UPSRTC vs. State of U.P. ( (2005) 1 SCC 444 )). When a particular decision has become final, and binding between the parties, it cannot be set at naught even on the ground that such a decision is violative of the provisions of the Constitution. So far as the parties are concerned, they will always be bound by the said decision. When a particular decision has become final, and binding between the parties, it cannot be set at naught even on the ground that such a decision is violative of the provisions of the Constitution. So far as the parties are concerned, they will always be bound by the said decision. (Supreme Court Employees Welfare Association vs. Union of India ( AIR 1990 SC 334 )). An order passed by a Court having jurisdiction over the subject-matter, and over the parties, cannot be ignored as a nullity unless such erroneous orders are corrected in accordance with law. Such orders bind the parties in a subsequent litigation or before the same Court in the subsequent stage of the proceedings. (Barkat Ali vs. Badrinarain (AIR 2001 Rajasthan 51)). Reference in this regard may be made to Wade and Forsyth on Administrative Law, 9th Edn., p. 243, wherein it is stated : "One special variety of estoppel is res judicata. This results from the rule which prevents the parties to a judicial determination from litigating the same question over again, even though the determination is demonstrably wrong. Except in proceedings by way of appeal, the parties bound by the judgment are estopped from questioning it. As between one another, they may neither pursue the same cause of action again, nor may they again litigate any issue which was an essential element in the decision. These two aspects are sometimes distinguished as cause of action estoppel and issue estoppel". In The Doctrine of Res Judicata, 2nd Edn. by George Spencer Bower and Turner, it is stated : "A judicial decision is deemed final, when it leaves nothing to be judicially determined or ascertained thereafter, in order to render it effective and capable of execution, and is absolute, complete, and certain, and when it is not lawfully subject to subsequent rescission, review, or modification by the tribunal which pronounced it". (Ishwar Dutt vs. Land Acquisition Collector ( (2005) 7 SCC 190 )). Matters in controversy, in writ proceedings under Article 226, decided after full contest, after affording fair opportunity to the parties to prove their case, by a court competent to decide it and which proceedings have attained finality, will operate as res judicata in subsequent proceedings on the same matters in controversy between the same parties. Matters in controversy, in writ proceedings under Article 226, decided after full contest, after affording fair opportunity to the parties to prove their case, by a court competent to decide it and which proceedings have attained finality, will operate as res judicata in subsequent proceedings on the same matters in controversy between the same parties. (Gulabchand Chhotalal Parikh vs. State of Gujarat ( AIR 1965 SC 1153 ); State of Punjab vs. Bua Das Kaushal ( AIR 1971 SC 1676 )). The rule of conclusiveness of judgments, as to the points decided earlier of fact, or of law, or of fact and law, in every subsequent proceeding between the same parties is the rule of res judicata. Once a matter which was the subject-matter of a lis stood determined by a competent Court, no party can, thereafter, be permitted to reopen it in a subsequent litigation. The principle of res judicata envisages that a judgment of a Court of concurrent jurisdiction directly upon a point creates a bar as regards a plea, between the same parties in some other matter in another Court, where the said plea seeks to raise afresh the very point that was determined in the earlier judgment. (Swamy Atmananda v. Swami Bodhananda ( AIR 2005 SC 2227 ); Iswar Dath ( (2005) 7 SCC 190 )). Issues which have been concluded inter parties cannot be raised again in proceedings inter parties. (State of Haryana vs. State of Punjab ( 2004 (12) SCC 673 )). W.P.M.P. No. 843 of 2009 is ordered and, consequently, the prayer in the writ petition stands amended. The assessment orders for the three years 2000-01, to 2002-03, being contrary to the orders passed by this Court in W.P. No. 22175 of 2000 which orders, both interim and final, are binding inter-parties, would necessitate a declaration that they are void. The assessment orders are, accordingly, quashed. This, however, is not end of the matter. The Full Bench, in Panchalingala Carbonic Gas Pvt. Ltd. (Vol. 40 APSTJ 41), (which judgment was followed by the Division Bench in W.P. No. 22175 of 2000 dated 02.09.2005), held that it is only if the industrial unit had not collected sales tax during the relevant period was the government disabled from directing them to pay sales tax and not otherwise. 40 APSTJ 41), (which judgment was followed by the Division Bench in W.P. No. 22175 of 2000 dated 02.09.2005), held that it is only if the industrial unit had not collected sales tax during the relevant period was the government disabled from directing them to pay sales tax and not otherwise. While Sri S. R. Ashok, Learned Senior Counsel appearing on behalf of the petitioners, would assert that the petitioners had not collected sales tax from its customers, this is, however, a matter of enquiry by the 1st respondent and this Court would not take upon itself the task of examining the records and conclusively determine whether or not the petitioner had collected sales tax from its customers in the three assessment years aforementioned. We consider it, appropriate, therefore, to remand the matter back to the 1st respondent - Commercial Tax Officer who shall examine the records for these three assessment years, and any other records which the petitioner may choose to produce before him to establish that they had not collected sales tax, and, thereafter, pass orders afresh in accordance with law. The writ petition stands disposed of accordingly. However, in the circumstances, without costs.