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No respite for Delhi as farm smoke in the air
Delhi's air quality plunged into the "severe" zone on Thursday due to smoke from Punjab's burning paddy fields, with no relief in sight.
The Capital once again struggled to shrug off the grey sheet that has shrouded it for five days, with waves of smoke from Punjab’s burning paddy fields pushing Delhi’s air quality index (AQI) deeper into the “severe” zone on Thursday.
Delhi has been shackled in a pollution hot box since Diwali, with farm fire smoke feeding the city’s bad air crisis, and still winds doing little to free the air of pollutants.
This run was extended on Thursday, when Delhi clocked an AQI of 419 at 4pm, a reading firmly in the hazardous “severe” zone, according to the Central Pollution Control Board’s (CPCB) official bulletin. By 10pm, this number surged to 440.
Delhi’s AQI was severe on Wednesday too, with a reading of 401 according to CPCB’s initial bulletin. But the agency later revised this number to 398 (very poor), citing a faulty reading. However, a difference of three AQI points is no more than a technicality. The air is just as filthy in both cases, with devastating long-term health impacts for people across ages.
Thursday’s pollution was driven largely by farm fire smoke, with authorities in Punjab failing to get a grip on the uncontrolled burning of paddy fields as the rabi sowing season nears.
While the number of fires in the agrarian state dipped to 1,271 (from 2,544 a day ago), stubble smoke usually takes between one or two days to travel from Punjab to Delhi, depending on the direction and speed of high transport winds, said Mahesh Palawat, vice-president, at Skymet, a private weather forecaster.
“If the wind speed is strong – up to 10-15km/hr – it takes around 24 hours or even less. If it is slower, it can take up to 36 hours,” he said, adding that the impact of farm fires recorded the previous day reflects in Delhi’s air the next day.
So, the Capital is now feeling the combined effects of a rise in farm fires in the agrarian state and northwesterly winds over the previous six days.
Punjab has now recorded 31,932 fires between September 30 and November 16 this year. The count at the same time last year was 46,822. According to local officials, around 95% of state’s paddy fields have been cleared or harvested.
After almost stopping on the two days before Diwali – November 10 and November 11 – due to a censure by the Supreme Court, farm fires in Punjab have been back to the levels seen earlier this month from November 12.
On November 11, Punjab logged 106 farm fires, which jumped to 987 the next day and further to 1,624 on November 13. The surge continued with 1,776 on November 14 and 2,544 a day later.
For much of Thursday, just like previous two days, winds blew in from the northwest, helping this noxious smoke travel hundreds of kilometres and settle over the national capital.
However, the direction of winds switched to northeasterly later in the day, with forecasters predicting that Delhi’s pollution levels will, as a result, drop marginally over the next few days.
Still, the AQI will likely remain “very poor” over the weekend and the initial parts of next week, the predictions said.
“Delhi’s air quality is likely to be in the ‘very poor’ category from Friday till Sunday. The outlook for the subsequent six days shows the air quality is likely to remain in the ‘very poor’ category,” said the forecast by the Union ministry of earth sciences’ Early Warning System (EWS).
CPCB data also showed that the first half of November ended with an average AQI of 376 for the city, an increase from 345 in the corresponding period last year, but less polluted than 2021 (385), 2020 (387) and 2019 (376).
Delhi’s blushes were saved by the spell of between November 9 and 10, which pushed the AQI below 300. Without those three days — the AQI was 279 on November 10, 220 on November 11 and 218 on November 12 — Delhi’s average for the first fortnight of November would be 410.
The grey tint across the city also impaired visibility, especially in the morning. The visibility dipped to 200 metres in parts of the city at 7.30am, said the India Meteorological Department (IMD).
