Tax deduction at source under GST: commencement set for specified public entities, deduction date to be notified after Council recommendation. The Government appoints the 18th day of September, 2017 as the date on which sub section (1) of section 51 of the Goa GST Act becomes operative for specified public authorities, government established societies and public sector undertakings; however, the obligation of those persons to deduct tax from payments to suppliers of taxable goods or services will take effect from a subsequent date to be notified by the State Government on the Council's recommendation.