Late fee waiver for GST returns: conditional relief and a limited filing window for delayed GSTR-3B submissions. Rationalises late fee for delayed furnishing of FORM GSTR-3B by prescribing, by class of registered person based on aggregate turnover, cure periods and nominal waiver floors for specified tax periods. Grants a limited reopening window for returns due July 2017-April 2021, waiving late fee amounts in excess of a prescribed floor (with a lower floor where central tax payable is nil) provided returns are filed within the notified period, and prescribes fixed waiver thresholds for late filings from June 2021 onwards.