Temperature in Mumbai dips, brings down air quality to ‘poor’

Air Quality Index was 202 during the day, that increased to 210 (poor) by the evening.

mumbai Updated: Nov 15, 2017 00:26 IST
Badri Chatterjee
Badri Chatterjee
Hindustan Times
Mumbai news,Air Quality Index,SAFAR
Smog over Parel on Tuesday.(Shashi S Kashyap/ HT PHOTO)

The drop in night temperatures has caused a spike in Mumbai’s pollution levels, with the air quality index (AQI) – a pollutant measuring indicator - on Tuesday entering the ‘poor’ category for the first time since Diwali.

AQI was 202 during the day, that increased to 210 (poor) by the evening. The System of Air Quality Weather Forecasting and Research (SAFAR), which tabulates the AQI, estimated a further rise in pollution levels with a predicted AQI of 215 (poor) for Wednesday. Delhi, where the pollution index crossed 400 recorded an AQI of 389 (very poor), Ahmedabad 253 (poor), and Pune recorded 93 (satisfactory), on Tuesday.

AQI levels between 0-50 is good, 51-100 is satisfactory, 101-200 is moderate, 201-300 poor, and 301-400 is very poor. Mazgaon and Navi Mumbai recorded the worst air in the city with AQI levels at 311 (very poor) at both locations.

On October 19 (Diwali), Mumbai had recorded poor AQI levels at 204 and 316 (very poor) on October 20, a day after Diwali.

Researchers attributed the rise in pollution to a drop in temperatures. “The minimum temperature has seen a decline in Mumbai over the past three days. This has allowed pollutants to be trapped closer to the surface,” said Gufran Beig, project director, SAFAR. “However, we expect air quality to improve later on in the week as temperatures are expected to rise.

Meanwhile, night temperatures were two degrees Celsius below normal on Monday as the city recorded 19.3 degrees Celsius, lowest this season, at the Santacruz weather station. However, the minimum temperature increased on Tuesday to 20.4 degrees Celsius, 1.1 degree Celsius below normal. On Tuesday, Colaba recorded 22 degrees Celsius, 1.3 degree Celsius below normal.

Even day temperatures were below the normal mark on Tuesday. While Santacruz recorded 30.8 degrees Celsius, almost 3 degree Celsius below normal, 32.3 degrees Celsius was recorded at Colaba, 1.2 degree Celsius below normal.

Officials from the weather bureau said that temperatures are likely to increase by Thursday. “Over the past four days, cool northerly winds were prevailing over the city. However, this is likely to change as a western disturbance is approaching north-west India. It is causing rainfall in northern parts, and as a result, the wind direction will change to south-westerly (warm) winds, which will lead to a rise in temperature,” said Mrutunjay Mohapatra, head of climate services, India Meteorological Department (IMD).

First Published: Nov 15, 2017 00:26 IST