Commencement of Section 51 under Punjab GST Act applies to government-controlled authorities, societies and public sector undertakings upon notification. The Governor notifies a commencement date in October 2018 for section 51 of the Punjab GST Act, superseding the earlier October 2017 notification, and prescribes that section 51 will apply to authorities or boards with majority government participation, societies established by government under the Societies Registration Act, and public sector undertakings, subject to preservation of prior actions.