The Standards of Weights and Measures (Enforcement) Act,1985
Section 34. Custom or usage requiring delivery of additional quantities to cease
(1) Any custom, usage, practice or method of whatever nature which permits a person to demand, receive, or cause to be demanded or received, any quantity of article, thing or service in excess of, or less than, the quantity specified by weight, measure or number in any contract or other agreement in relation to the said article, thing or service, shall be void.
(2) Where, in relation to any commodity sold by number, there is a Custom or usage of delivering a fixed number of such commodity in addition to the number of commodities paid for, such Custom or usage shall, on and from the commencement of this Act, cease.