Input Tax Credit matching requirement: supplier must rectify mismatches within the rectification period or recipient must reverse the credit. Section 29 conditions confirmation of Input Tax Credit on matching recipient inward details with supplier outward details in a valid return. If a mismatch arises, the supplier must rectify the discrepancy within a prescribed rectification period; if the mismatch persists, the recipient is required to reverse the Input Tax Credit for the unmatched supplies.