Several cities, including Agra, Ahmedabad, Patna, Delhi and Varanasi, were choked by particulate matter pollution on Sunday, when the northern parts of the country celebrated Deepavali.
Fireworks and stagnant air led to a precipitous dip in air quality in a third of the 29 cities monitored by the Central Pollution Control Board (CPCB).
Concentrations of fine particulate matter rose to levels that harm respiratory health in normal people and severely debilitate those with illnesses. The Air Quality Index (AQI) reading for Agra was 384, Ahmedabad 385, and Faridabad and Delhi the worst, at 428 and 445.
An AQI of 100 is the limit for good air quality. Bengaluru, Chennai and Mumbai were in the ‘moderate’ to ‘satisfactory’ category, similar to last year’s Deepavali. Hyderabad improved from ‘poor’ to ‘satisfactory.’
Poor air quality was forecast by agencies in the run-up to Deepavali. The AQI has deteriorated from October 27 in northern cities, primarily due to an ‘anticyclone’ effect – a shift in wind-patterns that prevents dust and particulate matter from being flushed out.
Deepavali and dipping temperature raised concentrations of PM2.5 (particulate matter 2.5 micrometres and smaller) and PM10 unlike in 2015, when winds swept pollutants away, the System of Air Quality Weather Forecasting and Research, a research unit run by the Indian Institute of Tropical Meteorology, Pune, said.
Without rain or other wind systems, poor regional air would linger, an official said. “We don’t yet see any weather system that will take away the accumulated pollutants, though the effect of crackers will dissipate soon,” K.J. Ramesh, Director General, India Meteorological Department, told The Hindu. A CPCB official said the Deepavali pollution could not strictly be compared year-on-year because it varied over the months and was influenced by changing weather. It was too early to assess relative impact of firecracker smoke on Delhi’s air.
