The Delhi government has imposed a ban on the plying of BS-IV diesel and BS-III petrol four-wheelers in the national capital till December 9, in view of restrictions clamped by the Centre’s air quality panel under stage III of the Graded Response Action Plan.

Those violating the ban will have to pay a penalty of Rs 20,000. The air quality in Delhi remained in the “very poor” category on Tuesday.

“As per the directions provided under Stage III of the revised GRAP and under section 115 of the Motor Vehicle Act, 1988, it is hereby ordered that there shall be restrictions to ply BS-III petrol and BS-IV diesel LMVs (four-wheelers) in NCT of Delhi with immediate effect till December 9 or till downward revision in GRAP stage, whichever is earlier,” read an order issued by the transport department.

Vehicles deployed in emergency services such as ambulances and government work have been exempted from the ban.