Local pollutants led to the air quality oscillated between "poor" and "very poor" categories in the national capital on Monday as the authorities have further predicted a rise in the level of pollution. The overall air quality index (AQI) was recorded at 314 by the Central Pollution Control Board (CPCB), which falls in the "very poor" category.
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 is considered to be "severe".
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The air quality in the national capital is "very poor" and at present there is "insignificant intrusion (of pollutants) from outside of Delhi," said the Centre-run System of Air Quality and Weather Forecasting (SAFAR).
"It is an ideal time to ascertain the impact of local emissions on the pollution level of Delhi," it said.
Local emissions include pollutants from vehicles, construction activities and garbage burning, among others.
The authorities had earlier said vehicular emissions contribute to 40 per cent of the air pollution in Delhi.
The CPCB said in 19 areas of the national capital the air quality was in the "very poor" category, while in six areas it was recorded in the "poor" category.
The PM2.5 (fine particulate matter in the air with a diameter of less than 2.5 micrometre) level was recorded at 174 and the PM10 level at 358, it said.
Ghaziabad and Noida recorded "very poor" air quality. In Faridabad and Gurgaon, the air quality was "poor" and "moderate" respectively, the CPCB data showed.
Delhi's air quality has been in the "very poor" category for the past one week but on Saturday it had improved to "poor" category for a brief period. It again slipped into "very poor" category Sunday, the authorities said.