law: Standards of Weights and Measures (Enforcement) Act, 1985
  Chapter X: Provisions
  
  with Regard to any Custom or Usage Relating to the Sale of any Commodity,
  
  Whether by Quantity or Number, and Sale of Commodities by Heapse
  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 commodities in addition to the number of
  
  commodities paid for, such custom or usage shall, on and from the commencement
  
  of this Act, cease.