Credit note issuance for returned goods: supplier must issue credit note and matched ITC adjustment ensures tax correction. Tax treatment for returned goods is governed by Section 34. The supplier may issue a credit note with prescribed particulars and must declare the credit note details in the returns for the month of issuance within the prescribed latest filing window. The supplier's reduction in output tax liability is matched against the recipient's reduction in Input Tax Credit in a valid return for the same or a subsequent tax period; adjustments are finally accepted only when the claimant reductions correspond and are communicated to both parties.