Why is there so much emphasis on changing over from petrol/diesel driven automobiles

CBSE Class 10 CBSE Class 10 Science
1

Why is there so much emphasis on changing over from petrol/diesel driven automobiles to CNG driven vehicles?

2

There is so much emphasis on changing over from petrol /diesel driven automobiles to CNG driven vehicles, because of the following reasons:
(i) It does not produce smoke.
(ii) On burning CNG it produces $CO_{2}$ and water.
(iii) It does not leave inburnt hydrocarbons, lead particulates etc., which pollute the environment.