Air quality

ernment of Punjab, a total of 43,181 farm fire incidents have been reported in the state since September 23.

“The main reason behind the deteriorating air quality is the slowing down of wind. On Monday, the wind speed was 10kmph, while on Sunday it was nearly 20kmph. The situation might deteriorate further till November 14. On November 15, 16 and 17, the wind speed will rise again,” said Kuldeep Srivastava, head of the India Meteorological Department’s (IMD) regional weather forecasting centre.

Scientists also blamed the change in wind direction from south-easterly to north-westerly, which, they said, is not only bringing in pollutants from the stubble-burning regions of Punjab and Haryana but also cold winds from the snow-clad Himalayan mountains. When the air is colder, it becomes heavier and thus unfavourable for the dispersion of pollutants. On Monday, the maximum temperature was 28.5 degrees Celsius, normal for this time of the year, while the minimum settled at 13.5 degrees Celsius, a notch below the season’s average.

After a marginal dip at 8am, the PM2.5 (fine particulate matter) — one of the most harmful aerosols — levels in the city’s air also saw an upward movement as the day progressed. CPCB data showed that at 8am, the average PM2.5 level was 180ug/m3; this increased to 212 at 12pm and 226 at 5pm, nearly four times the safe limit of 60. “It [the rise in pollution] worries me too. I worry about your family as much as mine. Through collective efforts, there’s 25% reduction in pollution for rest of year. Till October 10, Delhi air was good, after which it started going bad due to stubble burning. It happens every year at this time. We are working to find a solution,” tweeted Delhi chief minister Arvind Kejriwal.

Looking at the dip in the air quality, CPCB extended the ban on polluting industries in Delhincr till November 13. After that, the air quality is expected to improve and the ban may be lifted [from November 14]. “From November 14 winds are likely to be stronger resulting in faster dispersal of pollutants. We will