‘Poor’ air quality in Mumbai after 8 months, stagnant winds to blame

The pollutant-measuring indicator — air quality index (AQI) — in Mumbai on Tuesday entered the “poor” category after close to eight months this year.

The pollutant-measuring indicator — air quality index (AQI) — in Mumbai on Tuesday entered the “poor” category after close to eight months this year.

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According to the System of Air Quality Weather Forecasting and Research (SAFAR), the AQI was 218 (poor) during the day, which was 211 (poor) by the evening for PM2.5 pollutant — small pollutant particles that can easily enter the lungs and cause ailments — with three of 10 locations in the city recording very poor AQI.

The last time the city recorded poor AQI was on March 17 (272).

Researchers said the increase in pollution levels was due to stagnant winds over the city. “Owing to a sudden stagnation in wind speed on Tuesday and marginally higher moisture in the air as compared to previous days, pollutant particles were not dispersed and were suspended close to the surface,” said Gufran Beig, project director, SAFAR, adding that air quality was likely to fluctuate between the ”moderate” and “poor” categories through the rest of the month. “However, current poor air quality is temporary and is likely to improve as wind speed rises.”

The AQI is predicted to be 201 on Wednesday.

On Tuesday, the concentration for PM10 (larger coarser particles) was 182 micrograms per cubic metre (μg/m³), against the safe limit of 100 μg/m³ for 24 hours. PM2.5 levels were 94 μg/m³ against the safe limit of 60 μg/m³ for the 24-hour mark.

Mazgaon was the most polluted location in the city with an AQI of 311 (very poor) followed by Malad at 307 (very poor), and Chembur 303 (very poor). Navi Mumbai (225) and Bandra Kurla Complex (225) recorded poor air quality, while remaining locations either recorded “moderate” or “satisfactory” AQI. Worli had the cleanest air in the city at 75 (satisfactory).

SAFAR categorises AQI levels for PM2.5 in the 0-50 range as good; 51-100 as satisfactory; 101-200 as moderate; 201-300 as poor; 301-400 as very poor and above 400 as severe.

Meanwhile, the minimum temperature was a degree Celsius above normal at 23.2 degrees Celsius, while the maximum was at the normal mark at 34.2 degrees Celsius. A clear sky has been predicted for Wednesday with day and night temperatures expected to be 33 and 23 degrees Celsius.