Delhi air quality drops to ‘poor’ category; GRAP measures likely to be enforced

This year, GRAP became enforceable from October 1 onwards, however, the AQI had been in the moderate category till Thursday and Stage-I can only be put into force once the AQI crosses 200

Delhi’s air quality dropped to the “poor” category on Friday morning which is likely to prompt the Commission for Air Quality Management (CAQM) to enforce Stage-I measures under the Graded Response Action Plan (GRAP) today.

Delhi’s average AQI was recorded at 214 (poor) at 8am on Friday. (HT photo)

Delhi’s average AQI was recorded at 214 (poor) at 8am on Friday – a rise from Thursday’s 4pm reading of 177 (moderate).

This year, GRAP became enforceable from October 1 onwards, however, the AQI had been in the moderate category till Thursday and Stage-I can only be put into force once the AQI crosses the 200- mark.

According to GRAP, the adverse air quality is categorised into four different stages: stage 1 or ‘poor’ when the AQI ranges from 201-300, stage 2 or ‘very poor’ when AQI falls between 301-400, stage 3 or ‘severe’ when AQI ranges from 401-450, and stage 4 or ‘severe+’ when the AQI surpasses 450.

The category has 27 measures that need to be enforced, which includes shutting down construction and demolition (C&D) sites over 500sqms but are not registered with the government on its ‘web portal’ for dust management, encouraging offices to start unified commute for its employees to reduce road traffic, periodic mechanized sweeping and water sprinkling on roads and deployment of traffic police at all identified corridors with heavy traffic, among others.

Delhi’s average AQI has been on the decline for the past few days as it was 177 (moderate) on Thursday, 176 (moderate) on Wednesday, 155 (moderate) on Tuesday and 146 (moderate) on Monday.

On Thursday, forecasts by the Early Warning System (EWS) for Delhi – a forecasting under the ministry of earth sciences, had warned that the deterioration to poor may happen by Saturday.

Last year, Stage-I measures were put into action on October 5, when the AQI similarly hovered around the poor category.

Experts say a drop in mercury – which slows down dispersion of pollutants, alongside a rise in farm fires across the northern plains, is the reason behind the rising AQI.

Punjab has been recording close to 100 farm fires incidents for the last five days, including Thursday.

The daily fire count in the agrarian state was 98 on Thursday, 95 on Wednesday, 105 on Tuesday, 119 on Monday and 123 on Sunday.

Haryana, meanwhile, has recorded a combined 115 fires over these five days.

“As temperature dips, the atmosphere becomes stable. This makes it difficult for pollutants to disperse. The region is also seeing northwesterly winds, which brings pollutants to Delhi,” said Dipankar Saha, former head of CPCB’s air laboratory.