Section 7B(3)(a) in Delhi Motor Vehicles Rules, 1993
(a)be driven unless secured firmly on the front (but not on the windscreen) and the read exterior of the vehicle for display of the fact that the vehicle is being used for the purposes of a school. The colour of the board shall be golden yellow on which an iconographic representation of two school children(one girl and one boy ) shall be painted of height not less that 250 mm in black colour. Below the iconographic representation the words "SCHOOL BUS" shall be written in black colour and the height of the letters must be at least 100mm and the line thickness (width) of the type must be at least 16mm.