Delhi's air quality remained severe for the third day today, prompting authorities to issue warning to people to avoid staying outdoors for long and suspend construction activities, according to the Central Pollution Control Board (CPCB).
The 24-hour average concentration (rolling) of PM10 was 1,400 microgrammes per cubic metre (ug/m3), more than three times above the severe level, said Gufran Beig, a scientist at the Centre-run System of Air Quality and Weather Forecasting and Research institute (SAFAR). The severe level begins at 430 ug/m3.
"The pollution caused due to dust storm was expected to settle but the wind speed reduced yesterday, causing the dust that entered Delhi to get trapped in the atmosphere leading to prolonging of pollution," Beig said.
According to the CPCB, the air quality index (AQI) a measurement of the concentration of toxic particulate matter in the air at several places in Delhi remained over 500.
The PM10 level (presence of particles with diameter less than 10mm) was at 756 in Delhi-NCR and 785 in Delhi, leading to hazy conditions.
"Today even the PM2.5 level has gone to severe from very poor. It happened because of the reduced wind speed has led to accumulation of smaller particles and increasing the PM2.5 level," Beig said.
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.
A CPCB official said the air quality was gradually improving.
A Sudhakar, CPCB member-secretary, said people are requested to avoid staying outdoors for more than 3 to 4 hours. "There could be discomfort or breathing difficulties due to the pollution, Sudhakar said.
As the national capital region struggles with a severe dust pollution, Lieutenant Governor Anil Baijal today ordered stoppage of all civil construction activities across Delhi till Sunday as part of emergency measures that also include intensifying mechanical road sweeping.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)