Retrospective amendment to CENVAT credit rules bars fresh claims and mandates recovery of disallowed credits with interest. The amendment deems the second proviso to rule 3(3) of the CENVAT Credit Rules, 2002 effective from 1 March 2002, validates actions taken between that date and presidential assent to the Finance Bill, 2003, bars suits and enforcement for claimed credits that would be disallowed under the deeming, requires repayment of improperly taken credits within thirty days of assent with interest thereafter, empowers the Central Government to make retrospective rules for this purpose, and declares no new punishable acts arise from the section; 'CENVAT credit' retains its rule definition.