Mumbai: Air quality drops as monsoon retreat inches closer

As the monsoon retreat for this year gets closer, Mumbai's air quality has been witnessing a dip from the ‘good’ category to ‘satisfactory’. The Air Quality Index (AQI) recorded on Thursday for PM 10 was 68 and PM 2.5 was 44, while just 10 days earlier, on September 18, the AQI of PM 2.5 in Mumbai was 10 (lowest-ever recorded for the third time this year).

PM or particulate matter is a unit used to measure the size of the pollutants; the smaller the PM, the higher the toxicity levels. Also, lower the AQI value, cleaner the air, while a higher AQI indicates a greater level of air pollution and health concerns.

According to the India Meteorological Department (IMD), the tentative monsoon retreat date given for Mumbai this year is October 8, however, there is a possibility of a slight delay in the retreat. “Currently, the city is experiencing a mixed climate, with sunshine as well as cloudy skies and few spells of rainfall. This is due to the transition that we are witnessing from monsoon to the winter season," said Mumbai IMD official Sushma Nair. During rainfall, the city experiences good air quality because the pollutants get washed away, and during dry climate we see a rise in the bad air quality, she explained.

Meanwhile, some parts of the state like Palghar, Raigad and Thane have been given a yellow alert (light to moderate rainfall) along with thunderstorms and lightning.

On Thursday, the Santacruz observatory recorded a minimum temperature of 25.6 degrees Celsius and the maximum of 31.1 degrees Celsius, with 90 per cent relative humidity. Colaba experienced a minimum temperature of 26.4 degrees Celsius and a maximum of 31.1 degrees Celsius, with 87 per cent relative humidity.

According to the data from the System of Air Quality and Weather Forecasting And Research (SAFAR), other cities like Delhi breathed even worse air on Thursday, with a PM 10 of AQI 143, while Ahmedabad recorded an AQI of 69.