Particulate matter in Chennai air 4.5 times over safe levels prescribed by WHO, finds study

The city's annual PM 2.5 levels are 4.8 times higher than normal and have been at hazardous levels for 306 days (83.6%) in a year, says a study.

The city's annual PM 2.5 levels are 4.8 times higher than normal and have been at hazardous levels for 306 days (83.6%) in a year, says a study. As per the findings of 'Spare the Air', done by Green Peace India, the PM 2.5 levels were 23.81 g/m3 (micrograms per cubic metre) against the World Health Organisation-mandated safe levels of 5 g/m3.

The 24 hour PM 2.5 concentration was 56.33 g/m3, 3.8 times higher than the WHO-mandated 15 g/m3, said the study which, between September 2021 and 2022, recorded ambient air-quality from the city's sensors of Tamil Nadu Pollution Control Board and Central Pollution Control Board.

The city recorded an increase in pollution levels 12 times in October and November 2021 and 10 times in April and May 2022. While the city is better off than metros such as Bombay, Jaipur, Hyderabad, Lucknow and Bengaluru, where average pollution levels are upto 10 times higher than normal, experts and officials feel there's scope to do better.