The Centre's air quality panel on Tuesday directed authorities in Delhi and the adjoining National Capital Region to enforce measures under Stage I of the Graded Response Action Plan (GRAP) with immediate effect as pollution levels descended to the "poor" category.

The Commission for Air Quality Management (CAQM) said the Air Quality Index in Delhi was recorded at 211 on Monday and is likely to remain in the "poor" range in the coming days, according to forecasts by the India Meteorological Department and the Indian Institute of Tropical Meteorology.