The Central Motor Vehicles Rules,1989
Section 39. Use of trade registration mark and number
(1) A trade registration mark and number shall not be used upon more than one vehicle at a tune or upon any vehicle other than a vehicle bona fide in the possession of the dealer in the course of his business or on any type of vehicle other than the one for which the trade certificate is issued.
(2) The trade certificate shall be carried on a motor vehicle in a weatherproof circular folder and the trade registration mark shall be exhibited in a conspicuous place in the vehicle.