Waiver of interest .
40. The [Assessing Officer] may reduce or waive the interest payable under section 215 or section 217 in the cases and under the circumstances mentioned below, namely :—
(1) When the relevant assessment is completed more than one year after the submission of the return, the delay in assessment not being attributable to the assessee.
(2) Where a person is under section 163 treated as an agent of another person and is assessed upon the latter's income.
(3) Where the assessee has income from an unregistered firm assessed under the provisions of clause (b) of section 183.
(4) Where the previous year is the financial year or any year ending about the close of the financial year and large profits are made after the 1st March (or the 15th March in cases where the proviso to section 211 applies), in circumstances which could not be foreseen.
(5) Any case in which the [Deputy] Commissioner considers that the circumstances are such that a reduction or waiver of the interest payable under section 215 or section 217 is justified.
[(6) Nothing contained in this rule shall apply in respect of any assessment for the assessment year commencing on the first day of April, 1989, or any subsequent assessment year.]