Section 4(1)(a) in The Chennai Metropolitan Area Groundwater (Regulation) Act, 1987
(a)[ the number of wells that were in existence in the scheduled area immediately before the date of commencement of this Act;] [Substituted for clauses (a) and (b) by the Chennai Metropolitan Area Groundwater (Regulation) Amendment Act, 2002 (Tamil Nadu Act 37 of 2002) with effect from 21st November 2002.]