12. Re-opening of assessment at the instance of the assessee. - (1) Where an assessee assessed under section 11 makes an application to the Income-tax Officer within one month from the date of service of a notice of demand issued in consequence of the assessment, for the cancellation of the assessment on the ground--
(i)that he was prevented by sufficient cause from making the return required under sub-section (2) of section 8, or(ii)that he did not receive the notice issued under sub-section (1) of section 10, or(iii)that he had not a reasonable opportunity to comply, or was prevented by sufficient cause from complying, with the terms of the notice referred to in clause (ii),the Income-tax Officer shall if satisfied about the existence of such ground, cancel the assessment and proceed to make a fresh assessment in accordance with the provisions of section 10 or section 11.(2)Every application made under sub-section (1) shall be disposed of within ninety days from the date of receipt thereof by the Income-tax Officer;Provided that in computing the period of ninety days aforesaid any delay in disposing of the application which is attributable to the assessee shall be excluded.
