The Motor Vehicles Act, 1988
§61 — Application of Chapter to trailers
(1) The provisions of this Chapter shall apply to the registration of trailers as they apply to the registration of any other motor vehicle. (2) The registration mark assigned to a trailer shall be displayed in such manner on the side of the drawing vehicle, as may be prescribed by the Central Government. (3) No person shall drive a motor vehicle to which a trailer is or trailers are attached unless the registration mark of the motor vehicle so driven is displayed on the trailer or on the last trailer in the train, as the case may be, in such manner as may be prescribed by the Central Government.