High pollution levels persisted in Delhi

High pollution levels persisted in Delhi today as a thick blanket of fog enveloped the city and respirable particulates, trapped by moisture, hung low in the absence of strong wind movement.
The Central Pollution Control Board's (CPCB) air quality index (24-hour average) was in the 'severe' category with a reading of 403, which may affect healthy people and seriously impact those with existing respiratory ailments.
Five out of the nine monitoring centres of CPCB -- DTU, Punjabi Bagh, Anand Vihar, Mandir Marg, and Shadipur -- recorded air quality as severe.
The Palam weather office recorded visibility at zero metre at 8.30 AM. At Safdarjung observatory, it was marginally better at 150 metre.

The 24-hour-average (rolling) of PM 2.5 and PM 10, ultrafine particulates, were 188 and 350 micrograms per cubic metre respectively, violating the prescribed standards of 60 and 100 respectively by multiple times.
"PM 2.5 levels are 3-5 times higher than prescribed standards. Levels are going up with meteorological adversity in the absence of stringent emission control measures," TERI expert Sumit Sharma said.
Sharma said the city government's plan to install air purifiers in major traffic intersections will only have a "limited impact" on air quality in a very small area around the equipments.
According to experts, adverse conditions (like very low wind speed) do not allow pollutants to disperse due to which high pollution concentrations develop subsequently.