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Farm fires contribute 33% to Delhi’s PM 2.5
If you were wondering why the pollution situation had again become grim after two days of relative calm, here’s part of your answer: a change in wind direction has resulted in the capital bearing the brunt of crop fires in north Indian states.
Data show that pollution from crop stubble burning contributed to almost 33 per cent of Delhi’s PM2.5 concentration on Monday. The System of Air Quality and Weather Forecasting And Research — a body under the ministry of earth sciences — has been analysing the impact of crop stubble burning on Delhi’s pollution levels and data between October 21 and November 25 showed that farm fires contributed an average of 17.8 per cent to Delhi’s PM2.5.
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The maximum impact of crop stubble burning was on October 26 when it contributed to as much as 36 per cent. Monday’s 33 per cent was the second highest between this period as Delhi’s AQI once again touched poor. “There has been a significant intrusion of biomass-generated pollution (33 per cent) on November 5, which may decline rapidly now as upper winds are slow at 925hpa. Wind is still coming from the northwest region, which is unfavourable,” SAFAR said in an analysis on Monday.
According to the forecast system, the contribution of crop stubble burning, however, is likely to go down in the coming days, which may provide some respite. The forecast model showed stubble burning’s contribution go down to 14 per cent on Tuesday, 9 per cent on Wednesday — Diwali day — and 10 per cent on Thursday.
“Wind speeds at the upper level are decreasing and, so, the transportability will reduce, thus reducing contribution from stubble burning. Pollution in Delhi is likely to get stabilised,” a SAFAR scientist said.
While data this year showed a marked improvement in terms of the total number of fires occurring in parts of north India, the figure has spiked over the last one week. Nasa satellite imagery has detected 17,789 instances of crop burning between October 28 and November 3 compared to 18.496 last year during the same period. The number, however, was more than two times the fire incidents recorded in the week prior to that (8,171).
Anumita Roy Chowdhury of CSE, however, believes that efforts are likely to show rewards only by next year with implementation still lacking in a big way. “This year, everyone was looking at stubble burning with hope after the Centre provided a grant to provide incentives. We all know it is a problem. However, the challenge is about implementation now. Instances of crop burning this year are said to be lower but it will take some time to make a difference on ground. The scale of implementation has to be effective,” she said.