Poor to moderate” air on National Ambient Air quality (NAAQI) scale has enveloped Delhi as wind is flowing in from the stubble burning areas. Values of Particulate Matter (PM) 10 and PM 25 were at 191 Micro cubic Par Gram (µgm-3) and 94 µgm-3 respectively on Saturday, triggering a response from Delhi Pollution Control Committee (DPCC) that deployed marshals in 272 municipal wards in the national Capital.
The overall air quality index (AQI) of 245 was recorded at 10 am on Saturday which is the poor category. Ghaziabad and Gurugram recorded “very poor” air quality with PM values at 302 and 336, according the Central Pollution Control Board (CPCB) data.
On Friday, the AQI of Delhi was registered at 259. Earlier, it was predicted that a dust storm will hit the national Capital which would further deteriorate the air quality, but, at present, there are no indications of a big storm. Authorities are closely monitoring the situation, a senior official of the Supreme Court mandated Environment Pollution Control Authority said.
The drop in the air quality is due to change in direction of wind, which is now flowing from areas in Haryana and Punjab where stubble burning is taking place, a CPCB official said.
“This is the period of monsoon withdrawals and a low pressure system in the Arabian Sea is developing. Such large-scale process tends to calm the wind speed which is usual for this time.
“This tends to increase pollution level. The impact of local transport is insignificant so far,” said the Project Director at the Centre-run System of Air Quality and Weather Forecasting and Research (SAFAR), Gufran Beig.
An AQI between 0-50 is considered good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor, and 401-500 is considered severe.