Air quality improves to 'very poor', may worsen
NEW DELHI: Delhi's air quality was recorded in the "very poor" category Wednesday after overnight drizzle led to a slight drop in pollution level in the national capital, authorities said. The overall air quality index (AQI) was recorded at 348 which falls in the "very poor" category, according to data by the Central Pollution Control Board (CPCB). Twenty-eight areas in Delhi recorded "very poor" air quality while three areas recorded "poor' category", the data said.
Delhi's air quality has been oscillating between the "very poor" and "severe" categories after Diwali due to an increase in pollution because of the bursting of firecrackers. On Wednesday, the PM2.5 (particles in the air with a diameter of less than 2.5 micrometres) level was recorded at 202 while the PM10 (particles in the air with a diameter of less than 10 micrometres) was recorded at 327 in Delhi. An AQI between 0 and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".
Light rainfall brought the pollution level down, authorities said amid apprehensions that the rain might result in the rise of pollution level by increasing the pollutant holding capacity of air.
According to Indian Institute of Tropical Meteorology, the PM2.5 concentration will remain in very "poor category" on Wednesday. "The air quality is likely to improve in the next two days, but will remain in the 'very poor' category in Delhi-NCR till Thursday. The impact of biomass burning in north-west India is marginal over Delhi," it said.
Urban Emissions has forecast after lifting of the ban that the largest contribution to PM2.5 pollution on Wednesday would be due to power plants and diesel generator sets at 19.6 per cent followed by emissions by industries at 17.3 per cent. Household pollution would contribute 15.9 per cent, it has predicted.
Known to impact health severely by entering the bloodstream, the safe limit for PM2.5 is 25 units by international standards and 60 units by national standards.
Due to the rains, the larger suspended particles PM10 or particles with the diameter less than 10 mm, dropped from the "severe" to the "moderate" category on Wednesday morning, according to SAFAR.
"Weather has improved in Delhi, but since the system has moved, the region may see a slight increase in pollutants on Thursday due to calm winds. But after that, north-westerly winds will improve the air quality," Mahesh Palawat, Director of private weather forecast group Skymet, said.