Section 80AB of Income Tax Act "Deductions to be made with reference to the income included in the gross total income"
80AB. Where any deduction is required to be made or allowed under any section included in this Chapter under the heading "C.-Deductions in respect of certain incomes" in respect of any income of the nature specified in that section which is included in the gross total income of the assessee, then, notwithstanding anything contained in that section, for the purpose of computing the deduction under that section, the amount of income of that nature as computed in accordance with the provisions of this Act (before making any deduction under this Chapter) shall alone be deemed to be the amount of income of that nature which is derived or received by the assessee and which is included in his gross total income.
80AC. Where in computing the total income of an assessee
of any previous year relevant to the assessment year
commencing on or after-
(i) the 1st day of April, 2006 but before the 1st day of
April, 2018, any deduction is admissible under section 80-IA
or section 80-IAB or section 80-IB or section 80-IC or
section 80-ID or section 80-IE;
(ii) the 1st day of April, 2018, any deduction is admissible
under any provision of this Chapter under the heading
"C.-Deductions in respect of certain incomes", no such
deduction shall be allowed to him unless he furnishes a
return of his income for such assessment year on or before
the due date specified under sub-section (1) of section 139.