Exemption of unintended fish meal production waste granted for a specified retrospective period; previously collected tax not refundable. Exempts supplies of unintended waste generated during production of fish meal (heading 2301), excluding fish oil, for the period 1 July 2017 to 30 September 2019, exercised under the Goa Goods and Services Tax Act; no refund shall be made of tax already collected which would not have been collected had the exemption been in force throughout that period.