Section 80HHA amendment sets tiered investment thresholds by previous-year end dates, effective from April 1985. The Explanation below sub-section (8) of section 80HHA is amended by substituting three sub-clauses that establish distinct monetary thresholds tied to the date on which the previous year ends-prior to 1 August 1980; after 31 July 1980 but before 18 March 1985; and after 17 March 1985. The substitution is deemed effective from 1 April 1985 for application of the revised limits.