Composition levy under GST: simplified quarterly turnover based tax for eligible small taxpayers with restricted input tax credit access. Composition levy under GST is an optional simplified quarterly tax mechanism for small taxpayers below specified turnover thresholds, with distinct rates for manufacturers, restaurants and traders. Ineligible persons include casual or non resident taxpayers, suppliers of most services, inter State suppliers, certain manufacturers and sellers via e commerce operators. Composition taxpayers cannot claim input tax credit, must issue bills of supply, file quarterly Form GSTR 4, and comply with specific transition, opt in and withdrawal procedures using prescribed GST forms and ITC reversal filings. Enforcement follows prescribed show cause and order forms.