New Delhi, Jan 15 (IANS): The Centre on Wednesday re-imposed GRAP IV restrictions in the Delhi-National Capital Region (NCR) due to the worsening air quality. The Commission for Air Quality Management (CAQM) sub-committee decided to implement all actions under Stage-III ('Severe Air Quality of Delhi) and Stage-IV ('Severe+' Air Quality of Delhi) of the existing GRAP schedule, effective immediately, in addition to the Stage-I and Stage-II actions already in place, according to a statement.

"All actions of the GRAP schedule shall be implemented, monitored and reviewed by all the agencies concerned in the entire NCR to ensure that the AQI levels do not slip further. All implementing agencies shall keep strict vigil and intensify measures of the GRAP schedule. Citizens are requested to strictly adhere to the citizen charter under GRAP," the statement added.

The CAQM had, on January 12, revoked Stage-3 restrictions after the AQI in Delhi improved due to rainfall. Stage-IV restrictions include a ban on all construction activities, the entry of non-essential polluting trucks into Delhi, and the mandatory shift of school classes, except for classes 10 and 12, to hybrid mode.

Non-essential diesel trucks are prohibited from entering Delhi, and Delhi-registered BS-IV and older diesel-run heavy goods vehicles are banned, except for essential services, under Stage-IV.

During winters, the Delhi-NCR region enforces restrictions under GRAP, which categorises air quality into four stages – Stage-I (Poor, AQI 201-300), Stage-II (Very Poor, AQI 301-400), Stage-III (Severe, AQI 401-450), and Stage-IV (Severe Plus, AQI above 450).

Unfavourable meteorological conditions, combined with vehicle emissions, paddy-straw burning, firecrackers, and other local pollution sources, contribute to hazardous air quality levels in Delhi-NCR during winters.