Refund of input tax credit: formula and eligibility tightened for zero-rated supplies and export-related notifications under amended CGST Rules. The amendment prescribes that refunds for zero-rated supplies without payment of tax under bond or letter of undertaking be computed by the formula: Refund Amount = (Turnover of zero-rated supply of goods + Turnover of zero-rated supply of services) x Net ITC / Adjusted Total Turnover, and defines Net ITC, turnover measures, zero-rated services treatment, Adjusted Total Turnover and Relevant Period. It also allows refunds where suppliers have availed specified notifications, restricts amendment of registration particulars to dates on or after FORM GST REG-14 submission except by Commissioner order, and substitutes multiple registration and refund forms with revised verification and documentation requirements.