Exemption.

Where the Government or any authority under it is empowered to exempt any enterprises from any approval or inspection or any provisions relating thereto under any central Act, the Government or, as the case may be, any such authority sha[, subject to the provisions of such central Act, exercise such powers to grant such exemption to an enterprise established in the state for at least a period of three years from the date of issue of the acknowledgement certificate issued turder sub-section (2) of section 5.