Retrospective tax exemption: central tax not leviable on unintended fish meal production waste, with no refunds for collected tax. Clause 116 provides a retrospective exemption from central tax for supply of unintended waste generated during production of fish meal (heading 2301), except fish oil, for the period from 1st July, 2017 to 30th September, 2019, and stipulates that no refund shall be made of central tax already collected in respect of such supplies for that period.