Why shouldn't diesel buses be barred from entering Delhi, NGT asks states

Noting that ambient air quality was poor during winters, a bench headed by NGT Chairperson Justice Swatanter Kumar asked the states of Rajasthan, Uttar Pradesh, Uttarakhand, Punjab, Himachal Pradesh and Haryana to take clear decision on switching to CNG vehicles and buy buses with additional fuel cylinders to resolve the issue of providing sufficient fuel in these buses.

source: EconomicTimes