Mumbai breathes cleanest air this year, AQI at 156

This beats the lowest AQI recorded this year of 162 on January 16.

The city breathed its cleanest air this year on Monday as winds blowing from the sea cleared up pollutants in the air. An overall air quality index (AQI) — a pollutant measuring indicator — of 156 was measured, which was in the moderate category. This beats the lowest AQI recorded this year of 162 on January 16.

With the onset of westerly winds, the air has cleared up by the weekend but became poor on Sunday when an AQI of 252 was measured. (Anshuman Poyrekar/HT PHOTO)

The city's air quality had remained in the poor to very poor category since the beginning of the year owing to low temperatures. On January 8, the AQI was the worst at 317 (very poor).

However, with the onset of westerly winds, the air has cleared up by the weekend but became poor on Sunday when an AQI of 252 was measured.

The AQI was calculated by the System of Air Quality Weather Forecasting and Research (SAFAR) as the average of indices recorded at 10 locations in the city and suburbs. 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'.

“Air mass has formed in the ocean and wind blowing from the sea is cleaner than the air from landmass. Winds blowing from the north and west have cleared the air of pollutants. The air quality is expected to remain in the moderate to poor category,” said a spokesperson from SAFAR.

Of the 10 locations measured, only Navi Mumbai recorded 'very poor' air with the AQI being measured at 351.

Temperatures, meanwhile, increased. The Santacruz weather station recorded a minimum temperature of 20.2 degrees Celsius, 3 degrees above normal. The Colaba observatory of the Indian Meteorological Department (IMD) recorded a minimum temperature of 21.8 degrees Celsius, which was 3 degrees above normal.

Santacruz reported a maximum temperature of 31.6 degrees Celsius, which was 1 degree above normal. At Colaba, the maximum temperature was 29.4 degrees Celsius and was 1 degree below normal.

“The sky was somewhat cloudy on Monday. Parts of Maharashtra can expect a winter spell towards the middle of the week,” said KS Hosalikar, deputy director-general of western region, IMD.