India, Dec. 28 -- Two key restrictions under the Graded Response Action Plan (GRAP)-4 will now be enforced "permanently" in Delhi as part of measures to tackle 'severe' air pollution, environment minister Manjinder Singh Sirsa said on Friday.

The curbs relate to mandatory Pollution Under Control Certificates (PUCC) for refuelling vehicles and a ban on the entry of non-Bharat Stage VI (BS6) vehicles from outside the capital.

Air quality in the capital remained close to the "severe" category on Sunday, with the Central Pollution Control Board's Sameer app showing the overall air quality index (AQI) at 391 at 6 am. An AQI reading above 400 is classified as "severe."

Announcing the decision, Sirsa said petrol would not be dispensed to vehi...