Excise duty exemption: retrospective directive that unpaid duties on Copper Oxy Chloride need not be recovered. The Central Government, invoking section 11C, directs that the whole of the excise duty and special duty which, but for the prevailing practice, would have been payable on Copper Oxy Chloride under section 3 or the corresponding law, shall not be required to be paid in respect of such Copper Oxy Chloride on which those duties were not levied.