This appeal filed by assessee is against order of Appellate Assistant Commissioner dated 22-9-1983 for assessment year 1979-80 for which previous year ended on 30-6-1978. 2. In original assessment made on 8-4-1981 under section 143(1) of IT Act, 1961, investment allowance on intensive care unit was allowed as deduction. Later on Income-tax Officer noticed that investment allowance claimed by assessee in respect of intensive care unit was not allowable under Act. Since this was mistake apparent from record, show-cause notice under section 154 was issued to assessee. There was no response from assessee. ITO, therefore, rectified assessment under section 154 by disallowing investment allowance of Rs. 11,759. 3. In appeal before Appellate Assistant Commissioner assessee contended that mistake sought to be rectified was due to change of opinion and so rectification was not justified. AAC did not agree with contention of assessee and held that ITO was well within his jurisdiction in rectifying original assessment under section 154. Accordingly he confirmed order under section 154 passed by ITO. 4. Against order of AAC, assessee preferred present appeal. assessee's counsel conceded that allowance in original assessment of investment allowance on intensive care unit was mistake. However, he contended as under: Since assessment was completed under section 143(1) mistake has to be corrected only by resorting to section 143(2)(b). granting of investment allowance on intensive care unit made assessment, completed under section 143(1), incorrect as per sub-clause (d) of clause (1) of Explanation to section 143(3). This is specific provision in IT Act, 1961 to enable ITO to take remedial action if he was of opinion that assessment made under section 143(1) was incorrect, inadequate or incomplete in any material respect. Section 154 of IT Act, 1961 is general provision for rectification of mistakes apparent from record. Specific provision prevails over general provisions in Statute. So, ITO was not correct in resorting to section 154 of IT Act in present case. Consequently, order under section 154 under consideration is invalid. 5. arguments of departmental representative were to following effect: Section 143(2)(b) speaks of verifying 'correctness and completeness of return'. Section 154 speaks of rectification of 'mistakes apparent from record'. Section 143(2)(b) applies even if no assessment under section 143(1) was made. Further, there is no bar for ITO to take action under section 154 even though he could have taken action under section 143(2)(b). So, impugned order is valid. 6. We have considered rival submissions. Section 143(2)(b) comes into play only when ITO considers it necessary or expedient to verify correctness and completeness of return, whether or not assessment has been made under section 143(1). If ITO considers it necessary to verify correctness and completeness of return, he has to obtain prior approval of Inspecting Assistant Commissioner in cases where assessment has already been made under section 143(1). Then, after issue of notice under section 143(2) and after hearing such evidence as assessee may produce, if ITO is of opinion that assessment made under section 143(1) was 'incorrect, inadequate or incomplete in any material respect', as clarified in Explanation to section 143(3), he is bound to pass order in writing making afresh assessment of total income. obligation on part of ITO to make fresh assessment under section 143(3) arises only when he considers it necessary or expedient to verify correctness and completeness of return where assessment has been made under section 143(1) and issue notice with prior approval of IAC and finds that assessment made under section 143(1) is incorrect, inadequate or incomplete in any material respect as clarified in Explanation to section 143(3). But section 154 gives right to ITO to rectify any mistake apparent from records. word 'record' contemplated in this section includes order of assessment. In this particular case, ITO was not at all bothered about correctness and completeness of 'return'. He wanted rectification of mistake of wrongly allowing investment allowance in assessment made under section 143(1). So he had properly resorted to section 154 of IT Act. Had he wanted to consider it necessary or expedient to verify correctness and completeness of return he would have resorted to section 143(2)(b). 7. matter can be looked into from another angle also. circumstances in which order under section 154 or section 143(3), after complying with procedure under section 143(2)(b), may overlap and are not mutually exclusive. If in given case requirements of both sections 154 and 143(3) read with section 143(2)(b) are satisfied, application of neither can be ruled out. If requirements of section 154 are satisfied assessee cannot claim as of right that he should be dealt with only under section 143(3) read with section 143(2)(b) [See decision in A.H. Wheeler & Co. (P.) Ltd. v. ITO [1964] 51 ITR 92 (All.)]. Kerala High Court in case of R. Madhavan Nair v. CIT [1976] 105 ITR 813 considered powers of ITO under section 155(5) and 147(b) and held that it was open to ITO to resort to either of two provisions according to needs arising from facts and circumstances of given case. Where reassessment under section 147 and rectification under section 154 are both equally competent, department may take action under either section since two sections are not mutually exclusive. For this proposition following decisions may be seen: CIT v. D.R. Naik [1939] 7 ITR 362 (Bom.), Salem Provident Fund Society Ltd. v. CIT [1961] 42 ITR 547 (Mad.), V.S. Arulanadam v. ITO [1961] 43 ITR 511 (Mad.), Hira Lal Sutwala v. CIT [1965] 56 ITR 336 (All.) and P.C. Doshi v. Seventh ITO [1967] 65 ITR 187 (Bom.). In view of above we are unable to accept contention of assessee that ITO should have resorted to only section 143(2)(b) and not section 154. 8. In result, we uphold orders of lower authorities and dismiss this appeal. *** MANGALORE NURSING HOME v. INCOME TAX OFFICER