A.M. Sapre, CJ 1. By filing this writ petition under article 226/227 of the Constitution of India, the petitioner seeks to challenge show-cause notice dated 10th May, 2006 (Annexure D) issued by Superintendent of Taxes Guwahati Unit-A under section 37 of the Assam General Sales Tax Act ('the Act') for rectification of assessment order passed by the assessing authority on 17.2.2003 in relation to the petitioner's case for the assessment year 2000-01. 2. The facts of the case lie in a narrow compass. They, however, need mention in short to appreciate the controversy involved in the petition. 3. The petitioner No. 1 is a limited company registered as such under the provisions of the Companies Act having its registered office at New Delhi. The petitioner was having business activity of C&FA operations in State of Assam at the relevant time and, therefore, they got themselves registered as dealer and obtained the registration certificate (No GAU/ A/AGST-1152) under the Act. 4. The petitioner was assessed to payment of Sales Tax for the period 2000-01 by the assessing authority on their business turn over by an assessment order dated 17.2.2003. This order of assessment was modified by the assessing authority by re-assessment order dated 20.10.2003. 5. The petitioner felt aggrieved of the re-assessment order dated 20.10.2003 filed appeal before the Deputy Commissioner of Taxes (Appeals). By order dated 31.8.2004, the appellate authority allowed the petitioner's appeal and set aside the re-assessment order dated 20.10.2003. As a result, the original assessment order dated 17.2.2003 was restored. 6. The assessing authority then on 10.5.2006 issued the impugned show-cause notice to the petitioner under section 37 of the Act seeking to rectify the original assessment order dated 17.2.2003 on the grounds stated therein. It is against issuance of this show-cause notice; the petitioner felt aggrieved and filed this writ petition challenging its legality and correctness. 7. The only ground on which the impugned show-cause notice was challenged was that since the impugned show-cause notice was issued by the assessing authority beyond the period prescribed in section 37(1) of the Act and hence it was without jurisdiction. 8. Notice of the petition was served on the respondent (State). The respondent defended the impugned show-cause notice contending that it was issued within time prescribed under section 37(1) and, hence, it satisfied the requirement of section 37(1) ibid. 8. Notice of the petition was served on the respondent (State). The respondent defended the impugned show-cause notice contending that it was issued within time prescribed under section 37(1) and, hence, it satisfied the requirement of section 37(1) ibid. It was, therefore, contended that it be upheld for being probed on the merits on the grounds stated therein. 9. Heard Mr. K. Choudhury, learned counsel for the petitioners and Mr. S. Saikia, learned counsel for the Respondents. 10. So the short question which arises for consideration in this writ petition is whether show-cause notice dated 10.5.2006 issued by the assessing authority satisfied the requirement of section 37(1) ibid or in other words whether it can be held to have been issued within the time prescribed for rectification of the original assessment order? 11. Section 37 of the Act, which is relevant for disposal of the writ petition, reads as under : "37. Rectification of assessment and orders. - (1) The authority which made an assessment or order or passed an order in appeal or revision in respect thereof may, at any time within three years from the end of the financial year in which such assessment or order was made and of its own motion, rectify any arithmetical mistake or other mistake of a factual nature apparent from the record of the case, and shall even beyond such period, rectify and such mistake as is brought to its notice by a dealer or person affected by such order before the expiry of such time limit: Provided that no such rectification shall be made having the effect of enhancing the assessment unless the authority concerned has given notice to the dealer or person of its intention so to do and has allowed him a reasonable opportunity of being heard. (2) Where as a result of any order in appeal or revision under this Act any change becomes necessary in the order of assessment or penalty, the Appellate or Revision Authority may direct the appropriate authority to amend the order of assessment or penalty accordingly. (2) Where as a result of any order in appeal or revision under this Act any change becomes necessary in the order of assessment or penalty, the Appellate or Revision Authority may direct the appropriate authority to amend the order of assessment or penalty accordingly. (3) Where a rectification under, sub-section (1) or amendment under sub­section (2) has the effect of reducing the tax or penalty or other sum payable by the dealer a refund shall be due to the dealer and where any further amount of tax, penalty or other sum becomes payable the same shall be collected in accordance with the provisions of this Act. (4) Where any such rectification has the effect of enhancing the assessment, a notice of demand shall be issued for the sum so payable." 11. Mere reading of section 37 would go to show that it empowers the concern authority to rectify his order (assessment, appellate or revisionary) at any time within three years from the end of financial year in which such order was passed. The appropriate authority can rectify either of his own motion or at the instance of dealer/person and correct any mistake in his order. 12. Now coming to the facts of this case, the assessment order was passed on 17.2.2003. It, therefore, fell in the financial year 2002-03 whose year ending date was 31.3.2003. In this view, 3 years for issuance of show-cause notice to rectify the assessment order dated 17.2.2003 expired on 31.3.2006 whereas the impugned show-cause notice was issued on 10.5.2006. It was, therefore, apparently barred by time having been issued beyond the period of three years prescribed under section 37(1) ibid. In other words, in order to rectify the assessment order dated 17.2.2003, it was necessary for the assessing authority to have issued the show-cause notice on or before 31.3.2006 but not beyond this date because three years period prescribed under section 37(1) had to be counted from 31.3.2003 which expired on 31.3.2006. 13. Learned counsel for the respondent however contended that since the assessment order was re-assessed by order dated 20.10.2003 and appeal against the re-assessment order dated 20.10.2003 was decided in petitioner's favour on 31.8.2004 resulting in restoring the assessment order dated 17.2.003 and hence limitation should be computed from the end of financial year in which appellate order dated 31.8.2004 was passed and not any financial year prior to this date. This argument in our opinion is wholly misconceived and, therefore, not acceptable. 14. In our considered opinion, since the date on which the impugned show-cause notice was issued (10.5.2006), the assessment order dated 17.2.2003 was already in force having been revived as a result of appellate order passed on 20.10.2003, the limitation of three years had to be counted from the end of financial year in which the assessment order was passed. In other words, in order to determine the question of limitation what was relevant was the financial year in which the assessment order was passed. If the appellate authority wanted to rectify his order then the financial year in which the appellate order was passed was relevant for calculating the period of 3 years. It is for this reason, the argument pressed in service by the learned counsel for the respondent (State) has no merit and deserves to be rejected. 15. In the light of foregoing discussion we have no hesitation in holding that the impugned show-cause notice issued by the assessing authority on 10.5.2006 under section 37(1) was barred by limitation because it was issued by the assessing authority beyond the period of 3 years prescribed under section 37(1). It was, therefore, without jurisdiction and hence could not be given effect to for rectifying the original assessment order dated 17.2.2003. 16. As a result, the petition succeeds and is allowed. Impugned show-cause notice dated 10.5.2006 (Annexure D) is quashed by issuance of writ of certiorari. No cost.