Chennai's PM 2.5 level 4.8 times above normal: 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.