means, in relation to any person carrying on or deemed to be carrying on an enterprise within a region, a levy calculated and payable in relation to such enterprise in the manner determined by the Minister of Finance under section 12 (1) (b), at a rate from time to time determined by the council established for that region with the concurrence of the said Minister and which the said Minister shall publish by notice in the Gazette: Provided that different rates may be so determined in respect of different categories of enterprise;