Suspension of GST registration for mismatched returns and anomalies follows a thirty-day reply process before cancellation action. Suspension of registration under rule 21A(2A) applies where comparisons of returns with GSTR-1 outward supplies, inward supplies derived from suppliers' GSTR-1, or other authorised analysis reveal significant differences or anomalies indicating contravention of the Act or rules and an immediate revenue risk. The SOP provides interim implementation through FORM GST REG-31, electronic intimation, and a thirty-day reply mechanism in FORM GST REG-18. The proper officer may thereafter drop the proceedings in FORM GST REG-20, cancel registration in FORM GST REG-19, or revoke suspension and continue verification if needed.