Section 77(1) in The Central Motor Vehicles Rules, 1989
(1)The registration mark assigned under sub-rules (5) to (7) of rule 76 shall be clearly exhibited in reflecting colour both at the front and rear of the vehicle on the plain surface of a plate or part of the vehicle and the size of which shall be 41 centimetres by 14 centimetres(i)with deep blue background, the registration mark and the number being in white in the case of motor vehicles referred to in sub-rule (6) of rule 76;(ii)[with deep blue background, the registration mark and the number being in yellow] [Substituted 'with yellow background, the registration mark and the number being in black' by Notification No. G.S.R. 633(E), dated 23.6.2017 (w.e.f. 2.6.1989).], in the case of motor vehicles referred to in sub-rule (7) of rule 76;(iii)[ with light green background, the registration mark and the number being in white in case of motor vehicles referred to in rule 76-B.] [Inserted by GSR 395(E), dated 16.7.1997 (w.e.f. 16.7.1997).]
