Delhi’s air quality continues in ‘very poor category’

Delhi’s air quality is expected to reach the ‘upper end of very poor’ category by Sunday due to strong upper-level wind flow (blowing from the northwest), enhancing the transport of pollutants

Delhi’s air quality continued in the ‘very poor’ category on Saturday morning with an AQI value of 311 on the Central Pollution Control Board’s (CPCB) city-wise air quality index (AQI) at 9am. On Friday, AQI was in the ‘very poor’ category with a reading of 346 as per CPCB’s daily 4pm bulletin.

At least 27 monitoring stations in Delhi had readings in the ‘very poor’ category at 9am on Saturday. (Photo by Parveen Kumar/Hindustan Times)

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’.

At least 27 monitoring stations had readings in the ‘very poor’ category at 9am on Saturday, with Jehangirpuri having the worst AQI at 349.

The Commission for Air Quality Management (CAQM) in the National Capital Region’s (NCR) sub-committee on Graded Response Action Plan (Grap) Friday said actions implemented under Stage III will continue due to prevailing meteorological conditions. “Considering the significant spike in Delhi’s overall AQI from 260 to 346 in the last two days, north-westerly wind flow conducive to increasing the impact of farm fires on the AQI of Delhi and the need to continue with the steps to prevent deterioration of air quality...ongoing actions under Stage III of Grap shall continue and should not be withdrawn at this stage,” stated CAQM in a note on Friday.

In addition to the unfavourable north-westerly wind flow and slow wind speed, more farm fires from Punjab and other neighbouring states continued to contribute to the ‘very poor’ AQI on Friday.

According to the System of Air Quality and Weather Forecasting And Research (SAFAR) forecast, the air quality is expected to be in the ‘very poor’ category till Saturday. By Sunday, air quality is expected to reach the ‘upper end of very poor’ category due to strong upper-level wind flow (blowing from the northwest), enhancing the transport of pollutants.

“The rate of inflow of pollutants is likely to be more than that of dispersion, resulting in accumulation and deterioration of AQI to ‘upper end of very poor’ on Saturday and Sunday,” stated the forecast. While local surface winds with a speed of 12-24kmph might aid the dispersion of pollutants, the dip in minimum temperature will lead to the accumulation of pollutants, it added.

Saturday’s minimum temperature settled at 12.6°C, a degree below the normal for this time of year. According to the India meteorological department’s (IMD) weekly forecast, the maximum temperature is expected to hover around 29°C on Saturday.