Why CNG is better than diesel ?

All of these.

The correct answer is Option (4)- All of these.

After being censured very strongly by the Supreme Court, under its directives, the government was asked to take, within a specified time period, appropriate meas- ures, including switching over the entire fleet of public transport, i.e., buses, from diesel to compressed natural gas (CNG).

CNG burns most efficiently, unlike petrol or diesel, in the automobiles and very little of it is left unburnt.

Moreover, CNG is cheaper than petrol or diesel, cannot be siphoned off by thieves and adulterated like petrol or diesel.

The main problem with switching over to CNG is the difficulty of laying down pipelines to deliver CNG through distribution points/ pumps and ensuring uninterrupted supply.