Scrutiny of returns can trigger notices and corrective action, including assessment or recovery measures under GST law. Section 45 empowers the proper officer to scrutinize returns and related particulars, inform the taxable person of any discrepancies and seek an explanation; if the explanation is acceptable no further action is taken, but if it is unsatisfactory or corrective measures are not taken within the prescribed period the proper officer may initiate enforcement measures or determine tax and other dues under the relevant assessment provisions.