The air quality in the national capital on Saturday was in the 'poor' category, and the minimum temperature settled at 20.9 degree Celsius, a notch below the season’s average, officials said.

The Air Quality Index (AQI) in the national capital was recorded at 231 at 9 am. An AQI between zero and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'.

On Friday, the Centre's air quality panel directed authorities in the National Capital Region to enforce a ban on coal usage in hotels and restaurants, and to take punitive measures against polluting industries and thermal power plants as the air quality in Delhi plunged into the 'poor' category.

This action comes as part of the government's pollution control plan known as the 'Graded Response Action Plan' (GRAP) which is implemented in Delhi-NCR to combat air pollution during the winter season.

The Commission for Air Quality Management (CAQM), a statutory body responsible for proactively implementing GRAP, reported a "sudden decline" in air quality parameters in the region over the last 24 hours, with Delhi's AQI reaching 212 (in the 'poor' category).

"It is essential to invoke Stage-I of GRAP immediately throughout the entire NCR to take steps to prevent further deterioration of air quality in the region," the commission said in a statement.

GRAP categorizes actions 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 > 450).

Delhi's humidity was recorded at 62 per cent at 8.30 am on Saturday. The weather department predicted clear skies during the day. The maximum temperature is likely to settle around 37 degree Celsius, according to India Meteorological Department.

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