Missing Diwali PM2.5 Readings May Have Raised Delhi Pollution Average

Missing PM2.5 readings from Delhi monitoring stations on Diwali night may have caused the city’s average pollution level to be understated, according to an analysis by the Centre for Research on Energy and Clean Air. The analysis estimated that recording the missing readings at 1,000 micrograms per cubic metre would have raised the average PM2.5 level from 269 to 400 micrograms per cubic metre, an increase of 49%. The Central Pollution Control Board said its analysers could measure particulate matter only up to 1,000 micrograms per cubic metre. The analysis said including a 400 micrograms per cubic metre average would have put Monday’s AQI near the severe category, rather than 344, classified as very poor.