Question

in petrol/diesel driver automobiles to CNG driver vehicles
There is so much emphesis on changing over from per
because :
(1) On burning CNG produces O, and water.
(ü) It does not produce smoke.
(iii) It leaves unburent hydrocarbons.
(iv) It's heating capacity is less than that of petrol, diesel​

Answer 1

ii.it does not produce smoke