Delhi's air quality slipped to poor category Friday due to reversal of wind direction, which has now started flowing form the polluted Indo-Gangetic plains, authorities said.
The overall air quality index (AQI) of 259 was recorded at 4 pm Friday which is the poor category. On Tuesday, the air quality in the national capital was oscillating between poor to moderate category.
An AQI between 0-50 is considered good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor, and 401-500 severe.
The PM10 level (presence of particles with diameter less than 10mm) was at 229 in Delhi and the PM2.5 level (presence of particles with diameter less than 2.5 mm) in the city was 108, according to a data by the central government-run System of Air Quality and Weather Forecasting and Research.
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