<h1>CGST Rule-59(6): GSTR-1 Filing Blocked if GSTR-3B Not Submitted for Last Two Months or Previous Quarter.</h1> Rule-59(6) of the CGST Rules, 2017, effective from September 1, 2021, restricts filing GSTR-1 for registered persons who have not submitted GSTR-3B for the preceding two months or the previous quarterly tax period. The GST Portal will automatically enforce this rule, preventing GSTR-1 submission if the condition is unmet. Upon attempting to submit GSTR-1, the system will issue an error message if compliance with Rule-59(6) is not verified. Saved records in GSTR-1 will remain intact and can be filed once compliance is achieved. Taxpayers are advised to file pending GSTR-3B returns promptly to avoid disruptions.