(a)  issue notice to such person requiring him to furnish within such period, as may be specified in the notice, the return of income in respect of each assessment year falling within six assessment years and for the relevant assessment year or years referred to in clause (b), in the prescribed form and verified in the prescribed manner and setting forth such other particulars as may be prescribed and the provisions of this Act shall, so far as may be, apply accordingly as if such return were a return required to be furnished under section 139;

(b)  assess or reassess the total income of six assessment years immediately preceding the assessment year relevant to the previous year in which such search is conducted or requisition is made and for the relevant assessment year or years :

Provided that the Assessing Officer shall assess or reassess the total income in respect of each assessment year falling within such six assessment years and for the relevant assessment year or years :

Provided further that assessment or reassessment, if any, relating to any assessment year falling within the period of six assessment years and for the relevant assessment year or years referred to in this sub-section pending on the date of initiation of the search under section 132 or making of requisition under section 132A, as the case may be, shall abate :

Provided also that the Central Government may by rules made by it and published in the Official Gazette (except in cases where any assessment or reassessment has abated under the second proviso), specify the class or classes of cases in which the Assessing Officer shall not be required to issue notice for assessing or reassessing the total income for six assessment years immediately preceding the assessment year relevant to the previous year in which search is conducted or requisition is made and for the relevant assessment year or years:

Provided also that no notice for assessment or reassessment shall be issued by the Assessing Officer for the relevant assessment year or years unless—

(a)  the Assessing Officer has in his possession books of account or other documents or evidence which reveal that the income, represented in the form of asset, which has escaped assessment amounts to or is likely to amount to fifty lakh rupees or more in the relevant assessment year or in aggregate in the relevant assessment years;

(b)  the income referred to in clause (a) or part thereof has escaped assessment for such year or years; and

(c)  the search under section 132 is initiated or requisition under section 132A is made on or after the 1st day of April, 2017.

Explanation 1.—For the purposes of this sub-section, the expression "relevant assessment year" shall mean an assessment year preceding the assessment year relevant to the previous year in which search is conducted or requisition is made which falls beyond six assessment years but not later than ten assessment years from the end of the assessment year relevant to the previous year in which search is conducted or requisition is made.

Explanation 2.—For the purposes of the fourth proviso, "asset" shall include immovable property being land or building or both, shares and securities, loans and advances, deposits in bank account.

(2) If any proceeding initiated or any order of assessment or reassessment made under sub-section (1) has been annulled in appeal or any other legal proceeding, then, notwithstanding anything contained in sub-section (1) or section 153, the assessment or reassessment relating to any assessment year which has abated under the second proviso to sub-section (1), shall stand revived with effect from the date of receipt of the order of such annulment by the Principal Commissioner or Commissioner:

Provided that such revival shall cease to have effect, if such order of annulment is set aside.

Explanation.—For the removal of doubts, it is hereby declared that,—

(i)  save as otherwise provided in this section, section 153B and section 153C, all other provisions of this Act shall apply to the assessment made under this section;

(ii)  in an assessment or reassessment made in respect of an assessment year under this section, the tax shall be chargeable at the rate or rates as applicable to such assessment year.