Then follows the first proviso which runs thus: " provided that the Income tax Officer shall not issue, a notice under clause (a) of sub section (1) (i) for any year prior to the year ending on the 31st day of March 1941; (ii) for any year, if eight years have elapsed after the expiry of that year, unless the income, profits or gains chargeable to income tax which have escaped assessment or have been underassessed or assessed at too low a rate or have been made the subject of excessive relief under this Act, or the loss or depreciation allowance which has been computed in excess, amount to, or are likely to amount to, one lakh of rupees or more in the aggregate, either for that year, or for that year and any other year or years after which or after each of which eight years have elapsed, not being a year or years ending be fore the 31st day of March 1941; (iii) for any year, unless he has recorded his reasons for doing so, and, in any case falling under clause (ii), unless the Central Board of Revenue, and, in any other case, the Commissioner, is satisfied on such reasons recorded that it is a fit case for the issue of such notice:" It will thus be seen that where the Income tax Officer has reason to believe that due to any act of the assessee a full and accurate declaration was not made by the assessee for any year, with the result that part of his income has escap ed assessment for that year, the Income tax Officer may issue a notice under cl.(a) at any time.