Threshold limit for GST registration: suppliers exceeding prescribed turnover must register; special state lower limits and goods-only higher cap apply. Registration under GST is required when a supplier's aggregate turnover exceeds the prescribed threshold limit, with reduced limits for specified Special Category States and a possible raised limit for suppliers exclusively supplying goods as notified. Exemption by notification for persons exclusively supplying goods below a notified turnover ceiling is subject to exceptions including compulsory registrants, inter-state suppliers, voluntary registrants, and suppliers of specified goods and certain intra-State suppliers in listed States.