91. (1) Where it appears to the Deputy Commissioner of Taxes that any person may leave Bangladesh during the current financial year or shortly after its expiry and that he has no intention of returning, as assessment may be made in that year, notwithstanding anything contained in section 16, on the basis of the total income of such person- (a) if he has been previously assessed, for the period from the expiry of the last income year of which income has been assessed to the probable date of his departure from Bangladesh; and (b) if he has not been previously assessed, of the entire period of his stay in Bangladesh up to the probable date of his departure therefrom. (2) Assessment under sub-section (1) shall be made- (a) in respect of each completed income year included in the period referred to in sub-section (1), at the rate at which tax would have been charged had it been fully assessed; and (b) in respect of the period from the expiry of the last of the completed income years to the probable date of departure, at the rate in force for the financial year in which such assessment is made and that financial year shall be deemed to be the assessment year in respect of the income of the said period. (3) For the purpose of making an assessment under this section, the Deputy Commissioner of Taxes may serve a notice upon the person concerned requiring him to file, within such time, not being less than seven days, as may be specified in the notice,- (a) a return in the same form and verified in the same manner as a return under section 75 setting forth, along with such other particulars as may be required by the notice, his total income for each of the completed income years comprised in the relevant period referred to in sub-section (1); and (b) an estimate of his total income for the period from the expiry of the last of such completed income year to the probable date of his departure from Bangladesh. (4) All the provisions of this Ordinance shall, so far as may be, apply to the notice under sub-section (3) for purposes of assessment of tax as if it were a notice under section 77. (5) Nothing in this section shall be deemed to authorise a Deputy Commissioner of Taxes to assess any income which has escaped assessment or has been under assessed or has been assessed at too low a rate or has been the subject of excessive relief under this Ordinance but in respect of which he is debarred from issuing a notice under section 93.