In accordance with the rules, the side windows of buses should allow at least 50% of light. However, RTO officials claimed that the current advertisements on the AC buses allow only 30-40% of light to pass through.

Shyamlal Patnaik of Laqshya Media said: "This is limited to the window panel areas only. A perforated marked window film (one way vision film) is internationally accepted by all road transport authorities as acceptable media on the glasses of the windows of the vehicles. They give clear 40% to 50% visibility from inside but in India this is not acceptable as per the RTO rule."

The notice will mean an annual loss of revenue worth crores for BEST.

"Fleet graphics advertising is primarily about creating smart creative based on the surface that is available. Thus the notice does not affect the revenues of fleet graphics advertising," added Patnaik.