MUMBAI: As against the predicted heavy pollution on Diwali night on Thursday, Mumbai witnessed a moderate air quality index (AQI) at around 150-165 which meant breathing discomfort to the people with lungs, asthma and heart diseases. Thanks to near normal temperature, humidity and wind speed.
Since earlier this week, the city’s AQI was in the poor category, i.e., between 201 and 300. Mumbai was predicted to touch an AQI above 300, which is considered as very poor quality that causes respiratory illness in case of prolonged exposure.
However, SAFAR has forecast that the pollution levels will rise in the city and will reach a very poor category between Thursday night and Friday early morning. As per SAFAR's AQ forecast, the most polluted areas are expected to be Navi Mumbai, BKC and Chembur on both November 4 and November 5.
The main reason behind poor to very poor AQI, according to experts, is low breez and high humidity in the environment which is unable to disperse the smoke emanating from vehicles, garbage burning, construction dust and industries. Over and above, the firecrackers add fuel to the fire. HOwever, on Thursday the temperature, wind speed and humidity were close to normal levels.
In the AQI, the concentration of particulate matter 2.5 in air mainly decides the quality of air as its presence goes up in case of heavy polluting activities amid high humidity and low wind speed.
According to the System of Air Quality Weather Forecasting and Research (SAFAR), the concentration of PM 2.5 (the suspended pollutants 2.5 microns or smaller in size) was 75 micrograms/cubic metre, which is 1.2 times the daily safety limit. As per the National Ambient Air Quality Standards, the daily safe limit of 60ug/m3 for PM 2.5 should be maintained. PM 2.5 is one of the city’s most prominent pollutants.
The highest level of PM 10 and 2.5 are forecast for early morning hours i.e., between 1 am and 4 am on the night of November 4 and 5, but it will start to improve the next day, it said. As per the forecast, the concentration of PM 2.5 can go to 182ug/m3, which will be nearly three times more than the 24-hour safety limit. PM 10 concentration is likely to be 275 ug/m3 on Friday.
While 2020 saw poor AQI around 270 though fire cracker activities were less, the 2019 diwali was cleaner with better air quality due to low temperatures and gusty winds.
