Registration liability for suppliers: turnover thresholds trigger mandatory GST registration with lower threshold for special category states. Suppliers making taxable supplies in the State must register under the Act if aggregate turnover in a financial year exceeds twenty lakh rupees, with a ten lakh rupee threshold for supplies from special category States. Persons registered or licensed under existing law immediately before the appointed day are liable to register from that day. Transfers of businesses by succession, transfer as a going concern, or pursuant to amalgamation or demerger trigger registration obligations for the transferee or successor, with specific treatment upon issuance of a certificate of incorporation. Aggregate turnover includes supplies on own account or on behalf of principals and excludes job worker supplies treated as by the principal.