(1) If (a) the Income Tax Officer has reason to believe that by reason of the omission or failure on the part of an assessee to make a return of his income under section 22 for any year or to disclose fully and truly all material facts necessary for his assessment for that year, income, profits or gains chargeable for that year or have been underassessed, or assessed at too low a rate, or have been made the subject of excessive relief under the Act or excessive loss or depreciation allowance has been computed, or (b) notwithstanding that there has been no omission or failure as mentioned in clause (a) on the part of the assessee, the Income Tax Officer has m consequence of information in his possession reason to believe that income, profits or gains chargeable to income tax have escaped assessment for any year, or have been underassessed, or assessed at too ,low a rate, or have been made the subject of excessive relief under this Act, or that excessive loss or depreciation allowance has been computed, he may in cases falling under clause (a) at any time within eight years and in cases falling under clause (b) at any time within four years of the end of that year, serve on the assessee, or if the assessee is a company, on the principal officer thereof, a notice containing all or any of the requirements which may be included in a notice under sub section (2) of section 22 and may proceed to assess or reassess such income, profits or gains or recompute the loss or depreciation allowance and the provisions of this Act shall, so far as may be apply accordingly as if the notice were a notice issued under that sub section: Provided that : (1 ) the Income Tax Officer shall not issue a notice under this sub section, unless he has recorded his reasons for doing so and the Commissioner is satisfied on such reasons recorded that it ' is a fit case for the issue of such notice.