GST interest on delayed returns was revised with graded rates for specified turnover categories and return periods. Interest payable on delayed filing and payment of GST returns was revised for specified periods, replacing the earlier GSTR-3B reference with the broader category of taxpayers liable to pay tax but failing to do so. A graded interest structure was prescribed according to turnover and return category, with staggered nil, 9 per cent and 18 per cent rates for specified monthly and quarterly return periods. The amended notification was given retrospective effect from 18 May 2021.