Mumbai saw a spike in pollution levels a day after Diwali as the air quality index (AQI) – pollutant measuring indicator – went up to 320 till 10 am on Monday, falling under the ‘very poor’ AQI category.
Pollution readings from this Diwali were higher than last year’s 313 recorded by the System for Air Quality Weather Forecasting and Research (SAFAR).
The city woke up to a thin layer of smoke on Monday with empty firecracker shells spread across city streets. Mumbai’s AQI slightly improved by 1pm as it equaled last year’s level of 313. AQI levels between 201-300 falls under the ‘poor’ category and 301-400 is ‘very poor’, indicating a health risk for people sensitive to air pollution.
The health impact statement released by SAFAR for ‘very poor’ AQI levels warned citizens that the current air quality triggers a health alert for everyone. “Everyone may experience more or less health effects. People with existing heart or lung diseases such as asthma, chronic obstructive pulmonary disease, congestive heart disease, or ischemic heart disease should strictly avoid prolonged or heavy exertion. Everyone else should reduce prolonged or heavy exertion,” read the statement adding, “It is advisable to use pollution masks.”
As against a prediction of 334 by SAFAR for the day after Diwali, Monday morning’s reading was much lower owing to increase in wind speed and high temperatures, said researchers. “We expect Mumbai’s air quality to remain in the ‘very poor’ category through Monday. Along with the additional source of firecrackers, low temperatures and wind speed allowed pollutant particles to get trapped closer to the earth’s surface,” said Neha S Parkhi, senior programme officer, SAFAR. “We expect a further rise in wind speed, which will disperse pollutants and push the air quality into the ‘poor’ category by Tuesday.”
On Monday morning, the lead pollutant was particulate matter PM2.5 - small pollutant particles that can enter the lungs in PM10 - slightly larger, coarser particles, that increased by 20% due to the use of firecrackers, added Parkhi.
Both PM2.5 and PM10 levels were much above twice their safe limits. As against the permissible limit of 60 microgrammes per cubic metre (µg/m3) for PM2.5, levels were as high as 145.9µg/m3 in Mumbai. Similarly, PM10 levels were 228.9µg/m3 with a safe limit of 100µg/m3.
While all locations in Mumbai recorded high pollution levels on Monday morning, pollution hotspots in the city were – Malad, Andheri, Bandra Kurla Complex (BKC) and Mazgaon (see box). On the outskirts of Mumbai, Navi Mumbai recorded ‘very poor’ AQI levels for the fourth day-in-a-row.