Section 130(2) in The Central Motor Vehicles Rules, 1989
(2)Where the class label consists of adhesive material, it shall be waterproof and where it consists of metal or other substance on which the pictorial symbol and the text are printed, painted or affixed, they shall be affixed directly on such material and in every case, the surface of the vehicle surrounding the label shall be of a colour that contrasts vividly with the background of the class label.
