Strong northwesterly winds blowing towards the Capital since November 13 are transporting smoke from farm fires in Punjab and Haryana to Delhi, meteorological experts said, resulting in stubble burning becoming the largest contributor to Delhi’s PM 2.5 load.
Meanwhile, even as the paddy harvesting season in Punjab nears its end, there was no respite from farm fires as the northern state recorded 404 such incidents on Sunday — a sharp rise from the 136 stubble burning cases the previous day.
Delhi’s pollution levels entered the “severe” zone for the first time this season on November 13, with the Centre’s Decision Support System (DSS) — which calculates the contribution of farm fires to the Capital’s bad air on the basis of the actual stubble burning incidents a day earlier — pegging the contribution of farm fires to Delhi’s PM 2.5 concentration at 30.80%.
The daily contribution of farm fires to Delhi’s PM 2.5 load has remained over 25% since, with transport-level winds remaining northwesterly.
“Prior to November 13, the wind direction was mainly variable, meaning it kept fluctuating. These last five days, it has consistently been northwesterly, which not only leads to a layer of fog spreading across the Indo-Gangetic plains, but invariably brings smoke from Punjab and Haryana towards Delhi too,” explained Mahesh Palawat, vice president at Skymet meteorology.
Palawat said northwesterly winds are expected to continue, meaning farm fires will still remain a factor.
In Punjab, paddy is sown over three million hectares (7.5 million acres) during the Kharif — or summer crop — harvest in October-November, when farmers usually have a shorter window in which they need to clear their fields for the winter crop.
On Sunday, a majority of the farm fires in Punjab — 332 of the 404 incidents — were recorded in districts in the Malwa region, situated towards the south of the state, where the paddy harvesting is still on, even though less than 5% of farmlands are under paddy crop.
An agriculture department official said, “We were expecting negligible cases at this point of time but 404 is a big number, especially when less than 5% of paddy harvesting is pending. The district commissioners and police in the Malwa region have already directed to be extra vigilant to tackle the problem of stubble burning,” the official said.
He added that paddy harvesting is almost done in the state, and therefore the number of farm fire incidents is likely to record a steep drop over the next few days.
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