GRAP-III curbs were imposed in Delhi on Tuesday as air quality turned 'severe' in several areas. Non-essential construction and demolition activities are completely prohibited. All private BS-III petrol and BS-IV diesel LMVs (four-wheelers) in Delhi, Gurugram, Faridabad, Ghaziabad, and Noida are also restricted. A ban has also been issued on non-essential diesel-run BS-IV medium goods vehicles.