Notice requirement: government may exempt classes from issuing assessment notices for prior years following a search or requisition. Amendment to section 153A authorises the Central Government to make rules, published in the Official Gazette, specifying classes of cases in which the Assessing Officer shall not be required to issue notice for assessing or reassessing total income for the assessment years preceding the year in which search is conducted or requisition is made, except where any assessment or reassessment has abated under the second proviso; effective from July 2012.