North By Northwest: Wind direction spells trouble

NEW DELHI: Delhi’s pollution levels spiked by almost 50 points on CPCB’s Air Quality Index on Sunday with certain locations even breaching the 300 mark — used to denote the “very poor” category. While the overall AQI reading was 270 (poor) on Sunday, rising from 222 a day earlier, it was expected to turn “very poor” in the next 48 hours, forecasts showed.

On Sunday, Anand Vihar, Jahangirpuri, Mundka, Nehru Nagar, Vivek Vihar and Wazirpur stations were all in the “very poor” range with an average AQI of over 300.
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System of Air Quality and Weather Forecasting And Research (SAFAR), a body under ministry of earth sciences, stated that while the impact of crop stubble burning was not too huge at the moment, weather conditions and wind direction were likely to change the situation in the coming days. Low wind speeds, too, result in the trapping of pollutants.
“The overall air quality of Delhi is at the higher end of the poor category, as forecasted. The stubble burning activity in Haryana, Punjab and nearby border regions is moderate, but on the rise. Although the magnitude of biomass-related transport is not very huge, upper winds are flowing from north and north west towards Delhi with good speed and, hence, unfavourable for Delhi’s AQI with a share of more than 8% by tomorrow (Monday), as per our forecasting model,” SAFAR said in a statement on Sunday.
SAFAR’s model showed that the contribution of crop burning to Delhi’s overall PM 2.5 concentration was just 2% on Sunday, but this was likely to go up considerably by Tuesday. “The air quality is predicted to deteriorate towards the higher end of the ‘poor’ category to ‘very poor’ by tomorrow, mainly due to the changing local weather conditions. Further deterioration of AQI is expected by October 15, which will push it into the ‘very poor’ category,” SAFAR said in its report on Sunday.
The regional meteorological department said that low wind speeds were likely to continue in the region for the next few days with no major change expected in the temperatures either. Delhi’s maximum temperature on Sunday was 33 degrees Celsius, while the minimum was 20.8 degrees Celsius — a notch above normal. “Since Dussehra, we have seen a change in wind directions after the monsoon’s retreat. Wind speeds have also slowed down in Delhi-NCR, which has not allowed local pollutants to dissipate easily. This is likely to continue for the next few days,” said a Met department official.
The official said that north and northwesterly winds were unfavourable for Delhi’s air quality. “This will continue to bring pollution to Delhi through stubble burning as the pollutants can get trapped here,” he said.
A CPCB tasked force, formed to take action on the Graded Response Action Plan (GRAP), had on Saturday issued directions to agencies in the capital to step up action in those parts where the air quality was worse than the city average. “Agencies need to step up their actions. All state pollution control boards are advised to be vigilant and closely monitor air quality and actions by the implementing agencies,” the task force stated.