While calls by experts for emergency measures went unheeded by the government, several schools suspended outdoor activities and urged asthmatic kids to stay at home.
Safdarjung recorded visibility of 50m at 5.30am on Thursday. “We checked November data of the last 10 years and found that only once had visibility fallen below 50m (on November 20, 2011),“ said Ravinder Vishen, head, Regional Weather Forecasting Centre. The Centre for Science and Environment, which gathered data from the IGI airport met office, said the smog on Wednesday (visibility around 250m) was the worst for the month in 17 years, although this could not be independently verified.
Thursday’s air quality index, released by the System of Air Quality and Weather Forecasting And Research (SAFAR), was 500+, which meant it was beyond the 1-500 scale used for measuring air pollution. Such severe levels were recorded on October 31, the day after Diwali.
SAFAR also said the spike in air pollution in the last two days was likely to have been caused by smoke from crop-burning in Punjab and Haryana. “In the last two days till Thursday morning, the upper air wind direction has been northwesterly, which has brought pollutants from Punjab and Haryana to NCR even as winds close to the surface continue to be calm,“ said Gufran Beig, project director, SAFAR. Given the alarming air quality in the city, CSE sought emergency steps such as issuing health advisories, reducing vehicle numbers, shutting down the Badarpur power plant and taking stringent action against waste burning and crop-stubble fires in neighboring states. CSE quoted meteorologists to explain that a weather phenomenon called lower level anticyclone had developed around Delhi on November 2. There was no wind in the vertical column and this situation is expected to persist for a few more days, a statement by CSE said.
The Central Pollution Control Board’s air quality index for 24 hours was 432, the same as Wednesday. Values above 400 mean air pollution is “severe”. The PM 2.5 (fine, respirable pollution particles) peaked to 10 to 11 times the 24-hour national safe standard at locations such as R K Puram, Punjabi Bagh and Anand Vihar.