Summarize the following court judgment. ivil Appeal Nos. 667 668 of 1975. From the Judgment and order dated the 10 5 1973 of the Delhi High Court in Letter Patent Appeal Nos. 65 and 103 of 1969. F. section Nariman. Randhir Chawla. G. C. Sharma. Mrs. A; K. Verma	 Talat Ansari. Ravinder Narain	 and O. C. Mathur for the Appellant. G. L. Sanghi	 R. N. Sachthey and Girish Chandra for the Respondents. The Judgment of the Court was delivered by UNTWALIA	 J. In these appeals by certificate the question for determination is whether the exercise of the power of revision under sub section (3) of section 20 of the Bengal Finance (Sales Tax) Act	 1941 as extended to the Union Territory of Delhi hereinafter called the Act is subject to the period of limitation provided in sub section (2a) of section 11 or section 11A of the said Act. The requisite 3 facts lie in a narrow compass and may usefully be stated at the outset. The appellant who was carrying on the business of execution of building contracts was assessed to sales tax under the Act by the Sales Tax officer for the year 1955 56 by an order of assessment made on November 23	 1959. The appellants appeal before the Assistant Commissioner of Sales Tax succeeded in part. He held that the assessment for the first two quarters of the year 1955 56 was invalid having been made out of time. The case was	 therefore	 remanded to the Sales Tax officer for a fresh assessment in respect of the 3rd and 4th 249 quarters of the year. The Sales Tax officer in pursuance of the A appellate order of remand dated February 11	 1960 passed a fresh . assessment order on March 21	 1960. The Commissioner	 however	 after notice dated July 21	 1960 to the appellant	 by his order dated July 29	 1960 revised the appellate order of the Assistant Commissioner in exercise of his power under section 20(3) of the Act. He held that no part of the assessment for the year 1955 56 was barred and directed a fresh assessment to be made. A fresh assessment for all the four quarters was accordingly made by the Sales Tax officer on September 24	 1960. The appellant filed two writ petitions in the Delhi High Court challenging the order made in revision by the Commissioner and the fresh assessment order passed by the Sales Tax officer in pursuance thereof. A learned single Judge of the High Court allowed the writ applications on April 2	 1969 and quashed the impugned orders. The respondents took up the matter in letters patent appeal and succeeded before a Bench of the High Court. Hence these appeals by the assessees Mr. F. section Nariman appearing for the appellant contended: (1) That the appellate and the revisional authorities must exercise their appellate or revisional power within the period prescribed under sub section (2a) of section 11 of the Act. If their orders are final orders of assessment then directly they are exercising their powers under sub sections (1) or (2) of section 11. In case their orders are of remand for fresh assessment to the assessing` authority then also they must pass their orders within the periods aforesaid although under the proviso added in 1959 the assessing authority may have a further period of 4 years or 6 years	 as the case may be	 for passing a fresh assessment. (2) That the Commissioner while exercising the power in revision cannot overstep and ignore the period of limitation of 3 years provided in section 11A of the Art (3) That the authority mentioned in sections 11	 11A and 20(3) being the Commissioner	 the Commissioner is subject to the period of limitation provided in sections 11 and 11A even when exercising the revisional power under section 20(3). (4) That in any view of the matter the revisional authority must exercise the Dower in a reasonable manner and within a reasonable time. It cannot exercise the power of revision	 suo moto	 after a long lapse of time at its sweet will and pleasure. Under section 3 of the Act	 a hierarchy of officers has been constituted by the Chief Commissioner namely	 the Commissioner of Sales Tax	 Sales Tax officers and others to assist him. Section 11 of the Act deals with assessment of tax. The Sales Tax officer 250 exercising the powers as an officer to assist the Commissioner under section 11(1) of the Act can proceed to assess the amount of the tax due from a registered dealer within 18 months of the expiry of a particular period. A dealer who has been liable to pay tax under the Act but has failed to get himself registered can be assessed to tax under sub section (2). Then sub section 2(a) says: "No assessment under sub section (1) shall be made after the expiry of four years and no assessment under subsection (2) shall be made after the expiry of six years from the end of the year in respect of which or part of which the assessment is made :" A proviso was added to sub section (2a) w.e.f. October 1	 1959 By the Amending Act of 1958 and it reads as follows: "Provided that where such assessment is made in consequence of or to give effect to any order of an appellate or revisional authority or of a court	 the period of four years or six years	 as the case may be	 shall be reckoned from the date of such order. " lt is to be noticed that a period of limitation has been provided in section 11(2a) and no assessment either under sub section (1) or sub section (2) can be made after the expiry of the specified period. But where such an assessment is made by the assessing authority in consequence of or to give effect to any order of an appellate or revisional authority or any order of a court made in reference	 writ or in any other proceeding then under the proviso the period of limitation is to be reckoned from the date of such order. The Legislature has not provided any period. within which an order is to be made by an appellate or revisional authority of a court. Obviously it would have been unpractical and unworkable to do so. Section 20 deals with an appeal	 revision or review. If the appeal is filed in time the appellate authority in disposing of any appeal filed Under sub section (1) may (a) confirm	 reduce	 enhance or annul the assessment	 or; (b) set aside the assessment and direct the assessing r authority to make a fresh assessment after such further inquiry as may be directed. " For exercise of the appellate power in any of the manners mentioned above	 there is no limitation of time. If assessment can be reduced in appeal at any time it can be enhanced also without the fetter of time. If the assessment is set aside and the case remanded to the assessing authority to make a fresh assessment then the authority	 because of the proviso to section 11(2a)	 is obliged to make the fresh assessment within four years of the appellate order. Sub section (3) of section 20 reads thus: "Subject to such rules as may be prescribed and for reasons to be recorded in writing	 the Commissioner upon 251 application or of his own motion may revise any assessment A made or order passed under this Act or the rules there under by a person appointed under section 3 to assist him	 and subject as aforesaid	 the Chief Commissioner may	 in like manner	 revise any order passed by the Commissioner. " The Commissioner can revise any assessment made or order passed under the Act including the order of the appellate authority. The limits of the revisional power are not circumscribed in sub section (3)	 ut it goes without saying that they will be akin to the power of the appellate authority as mentioned in sub section (2). The revisional authority obviously	 as pointed out by this Court in the case of The State of Kerala vs K. M. Cheria Abdulla and Company(1) should not trench upon the power expressly reserved by the Act or the rules to other authorities and cannot ignore the limits inherent in exercise of those powers. Section 11A is one such power which deals with assessment and re assessment of tax in case of an escaped assessment or under assessment. Exercise of that power is subject to the limitations provided therein. In Rule 66(2) of the Delhi Sales Tax Rules	 1951 a period of limitation of 60 days has been provided for the filing of an application in revision which can be extended under the proviso appended to that rule on sufficient cause being shown. But no such limitation has been provided for the suo moto	 exercise of the revisional power. Mr. Nariman very strongly relied upon the majority decision of this Court in The State of Orissa vs Debaki Debi and others (2) and Submitted that the power of revision exercised by the Commissioners ill this case beyond the period of four years prescribed in sub section (2a) of section 11 was illegal and ultra vires. A close scrutiny of the argument will result in its rejection. In the Orissa case all the orders made by the Collector in exercise of his power of revision under section 23 of the Orissa Sales Tax Act were passed later than 36 months from the expiry of the period in respect of which the assessment was made. The High Court 's view that they were in contravention of section 12(7) which was a power of assessment or re assessment in case of an escaped or under assessment was not upheld. But it was found that the proviso to section 12(6) was in general terms. It was not only a proviso providing for the period of limitation for the first assessment but it governed the assessment made in exercise of the appellate or the revisional power. The main ratio decidendi of the case is that the proviso in section 12(6) is in reality an independent legislative provision unrelated to section 12(6). Therefore	 its operation was not confined to assessment under section 12 but applied to any assessment made under the Act. In the alternative it was also opined that assessment made in exercise of the revisional power was an assessment made under section 12. It was so said because if the appellate or the revisional authority would have directed the assessing authority to make a fresh assessment it could do so only under section 12 and then it (1) 16 Sales Tax Cases	 875. (2) 15 Sales Tax Cases	 153. 252 would be subject to the period for limitation of 36 months. It was pointed out in the majority decision of this Court that there would be an anomalous situation. If the appellate authority set aside the assessment and remanded it for fresh orders	 no fresh assessment could be made because of the period of limitation. But if instead of doing so the appellate authority affected the same assessment there would be no bar of limitation. In the present case in view of the proviso added to section 11(2a) the anomaly flows in the reverse direction. If the appellate or the revisional authority made a remand order the assessing authority could pass a fresh order of assessment within 4 years of such order. But if the higher authority itself revised the assessment then it would be barred by the rule of limitation provided in section 11 (2a) . To avoid such an anomaly Mr. Nariman suggested a construction to be put which neither solves the anomaly nor is warranted by the language of the provisions of the Act. Counsel submitted that in all cases the powers must be. exercised within 4 years of the period in respect of which an assessment was being made on a registered dealer. It will be wholly unreasonable almost impossible to say that all orders in appeal	 revision or reference must be passed within four years of the end of the period of assessment	 otherwise they will be barred. It does not solve the anomaly either. Even if the order of remand is made	 say	 just on the last day of the period of four years	 it will be competent to the assessing authority to make a fresh assessment within the further period of four years. The ratio of the case in Debaki Debi 's (supra) must be confined within its four corners and cannot be extended to the facts of the instant case. In The Swastik oil Mills Ltd. vs H. B. Munshi	 Deputy Commissioner Of Sales Tax Bombay (1) the decision of this Court in Debaki Debi 's case was distinguished on the ground that the provision of limitation of 36 months in substance was not a real proviso to the section in which it was placed but was in fact a period of limitation for all orders of assessment made under any other provision of the Orissa Act	 while in the Bombay Acts there was no such general provision prescribing a period of limitation for making an assessment. Reference to the period of limitation in section 11A of the Bombay Act which is a power of making assessment or re assessment in case of an escaped or under assessed assessments was also rejected. our attention was also drawn to the decision of a single Judge of the Punjab High Court	 Delhi Bench	 in Sir Sobha Singh & Company vs Commissioner of Sales Tax	 Delhi (2) wherein following the decision of this Court in Debaki Debi 's case it was held that an order of review made by the Commissioner under section 20(4) of the Act in effect is an order of assessment under section 11(1) and cannot be made r o after the expiry of the period prescribed under section 11(2a). The learned Judge in the course of his judgment made it clear that he was concerned with the construction of the Act as it stood before 1959 and was not obliged to consider the effect of the proviso added to section 11(2a) in 1959. It is not necessary to decide in this case whether without the aid of the proviso aforesaid the decision of the (1) 21 Sales Tax Cases	 383. (2) 18 section T. C. 416. 253 learned single Judge was correct or not but surely in face of the proviso it cannot hold good. In Commissioner of Commercial Taxes	 Bihar	 Patna vs Sheodutta Prasad Chandeshwar Singh (1) the review proceedings initiated by the assessing authority was held to be barred under the proviso to section 13(6) of the Bihar Sales Tax Act	 1947. But distinguishing the said decision another Bench of the Patna High Court held in Commissioner of Commercial Taxes	 Bihar vs Ashoka Marketing Ltd: (2) that the order of review passed by the Deputy Commissioner was not bared by time. The decision of the Patna High Court in Commissioner of Commercial Taxes	 Bihar	 Patna vs Sheodutta Prasad Chandeshwar Singh (supra) on identical facts was followed in Commissioner of Commercial Taxes	 Bihar vs Shiva Pujan Prasad Bhagat (3). But the principle decided in those cases cannot help the appellant. It may well be that if the assessing authority itself exercises the power of review it cannot circumscribe the bar of limitation provided in section 11 (2a) . But it will be unjust	 unreasonable and impracticable to say that the said bar of limitation must also continue to run at all stages of the proceedings	 namely	 the appellate	 revisional	 reference	 writ or any other stage. It was pointed out by this Court in Swastik oil Mills ' case (supra) that the Deputy Commissioner when seeking to exercise his revisional powers was not encroaching upon the powers reserved to other authorities. The powers were not exercised for the purpose of assessing or re assessing an escaped turn over. The revisional powers were sought to be exercised to correct what appeared to be an incorrect order passed by an Assistant Commissioner and for such a purpose proceedings could not possibly have been taken under section 11A. In the instant case also it could not be disputed that the view taken by the Assistant Commissioner in appeal was obviously wrong. The Commissioner while correcting that mistake in exercise of his revisional power was not doing anything which the Sales Tax officer was empowered to do under section 11A. He was merely setting right the illegality in the appellate order. The third point urged by the appellant is too obviously wrong to merit any detailed discussion. It was not the Commissioner who had passed the assessment order under section 11. That order was of the Sales Tax officer acting as an officer to assist the Commissioner for the purpose of assessment. The assessment order was interfered with by the appellate authority	 the Assistant Commissioner and the Commissioner was revising the order of the Assistant Commissioner. All cannot be treated as Commissioners for the purpose of the different powers exercised by the three different authorities. The use of the term "Commissioner" in the sections is merely for the purpose of describing and	 at any rate	 including the officer assisting the Commissioner as Commissioner. (1) 25 S.T.C. 114. (2) 33 S.T.C. 24	 (3) 	33 S.T.C. 466. 254 Apropos the fourth and the last submission of the appellant	 suffice it to say that even assuming that the revisional power cannot be exercised suo moto after an unduly long delay	 on the facts of this case it is plain that it was not so done. Within a few months of the passing of the appellate order by the Assistant Commissioner	 the Commissioner proceeded to revise and revised the said order. There was no undue or unreasonable delay made by the Commissioner. It may be stated here that an appeal has to be filed by an assessee within the prescribed time and so also a time limit has been prescribed for the assessee to move in revision. The appellate or the revisional powers in an appeal or revision filed by an assessee can be exercised in due course. No time limit has been prescribed for it. It may well be that for an exercise of the suo moto power of revision also	 the revisional authority has to initiate the proceeding within a reasonable time. Any unreasonable delay in exercise may affect its validity. What is a reasonable time	 however	 will depend upon the facts of each case. For the reasons stated above the appeals fail and are dismissed with costs. One set of hearing fee. P.B.R. Appeals dismissed.

Section 11 of the Bengal Finance (Sales Tax) Act	 1941 as extended to the Union Territory of Delhi provides for assessment of tax. Section 11A provides for assessment or reassessment in case of escaped or under assessment. Section 20 provides for appeals and revision. In 1959 the assessee was assessed by the Sales Tax officer for the assessment year 1955 56. The appellate authority remanded the matter holding that the assessment for the first two quarters was invalid having been made out of time. The Sales Tax officer passed a fresh assessment order in respect of the third and fourth quarter of the assessment year. In July	 1960	 the Commissioner under section 20(3) revised the appellate order holding that no part of the assessment was barred by limitation and directed fresh assessment. Appellant 's challenge to the order of tho Commissioner and the assessment order by the assessing authority was unsuccessful in the High Court. On appeal to this Court	 it was contended: (1) that the revisional authority must exercise his powers within the period of four years prescribed under section 11(2) (a) whether the order was a final order of assessment by him or a remand order for fresh assessment by the assessing authority; (ii) while exercising the power of revision the Commissioner cannot ignore the period of limitation of three years provided in section 11A; (iii) even when the Commissioner was exercising the revisional power under section 20(3)	 his power is subject to the periods of limitation provided because. in sections 11 11A and 20	 the authority mentioned is the Commissioner and (iv) the Revisional authority in the exercise of his power suo moto must exercise it within a reasonable time and not after a long lapse of lime. Dismissing the appeals	 ^ HELD: The Legislature has not provided any period within which an order is to be made by an appellant or revisional authority or a court. [250 E] F (1)(a) If the appeal is filed in time for the exercise of the appellate power either to assess or to direct assessment under section 20(2)	 there is no limitation of time. The limits of the revisional power in section 20(3) are akin to the power of the appellate authority in section 20(2). [250 F H] (b) No limitation has been provided for the suo moto exercise of the re visional power similar to the one provided in rule 66(2) of the Delhi Sales Tax Rules for filing an application in revision. [251 D] (c) It will be wholly unreasonable almost impossible to say that all orders in appeal	 revision or reference must be passed within four years of the end of the period of assessment and that otherwise they would be barred. The contention that there would be anomaly because of section 11(2a) in that if the appellate or revisional authority made a remand order	 the assessing authority could pass a fresh assessment order within four years of the remand order whereas if the appellate or revisional authority itself passed an order of assessment	 it should be done within four years. and that such an anomaly would be avoided if it was held that the revising authority must exercise its powers within four years in all cases is not warranted by the language of the provision. Further	 it does not solve the anomaly because even if the order 248 of remand is made just on the last day of the period of four years it would be competent to the assessing authority to make a fresh assessment within the further period of four years. [252 D; B C] (d) The State of Orissa vs Debki Debi [15 STC	 153 (SC] is distinguishable because the period of limitation in that case applied to assessment made i exercise of the appellate or revisional power also whereas in the present case there is no period of limitation for the exercise of appellate or revisional power While correcting a mistake in exercise of his revisional power the Commissioner was merely setting right the illegality in the appellate order	 and was not doing anything which the Sales Tax Officer was empowered to do under section 11A and so was not bound by the period of limitation mentioned in that section. [253] The State of Kerala vs K. M. Cheria Abdulla and Company	 16 Sales Tax Cases	 875	 referred to. (3) The order of assessment was that of the Sales Tax officer action as an officer to assist the Commissioner for the purpose of assessment. The term "Commissioner" is merely descriptive and includes the various officers appointed under section 3 to assist the Commissioner. There is a hierarchy of officers and all cannot be treated as "Commissioner" for the purpose of different powers exercised by them. [253 G Hl (4) Assuming that the revisional power could not be exercised suo moto after a long and unreasonable delay	 in the instant case there was no undue delay. What is reasonable time will depend upon the facts of each case. [254 A B]