Question

a vehicular standard for controlling air pollution

Answer 1

catalyst is a vehicular standard for controlling air pollution

Answer 2

Vehicular standards
Certain norms have been laid down under the title Euro/Bharat norms which are applicable to all automobiles, on the levels of emission given out ——stricter controls to be maintained in most large cities. Government of India has adopted auto fuel policy to effectively cut down sulphur and nitrogen oxides in the automobile exhaust.