Cocktail of slow winds, stubble fires gives Delhi its worst November AQI

The month usually sees two western disturbances, which often bring rain and stronger winds that disperse pollutants. This year, however, there were none.
The national capital recorded the maximum of 11 days in November when the index rose above 400, which is considered severe by the pollution watchdog. (Sanjeev Verma/HT PHOTO)
The national capital recorded the maximum of 11 days in November when the index rose above 400, which is considered severe by the pollution watchdog. (Sanjeev Verma/HT PHOTO)
Updated on Dec 01, 2021 06:47 AM IST
Copy Link
ByJasjeev Gandhiok

Air quality in the capital this year in November was the worst since the Central Pollution Control Board started maintaining detailed records in 2015, with average Air Quality Index (AQI) at 376. Delhi had last seen air this bad in November 2016, when average AQI was 374.

The national capital also recorded the maximum of 11 days in November when the index rose above 400, which is considered severe by the pollution watchdog, as it affects healthy people and seriously impacts those with prior illnesses.

Also Read | With list of dos and don’ts, Delhi pollution body asks residents to join air pollution fight

Besides human activities like construction and transportation that leads to harmful emissions, unfavourable meteorological conditions worsened the situation. Delhi usually sees at two western disturbances in the month, which often brings rain, but more importantly, stronger winds that help in dispersing pollutants. This year, there were none, according to R.K Jenamani, a scientist at the weather office.

“A western disturbance can bring rain and also increase wind speed a day before it is approaching, and when it is departing too,” Jenamani said. “This generally gives a two-three day window where air quality improves.”

Also Read | Delhi’s pollution drops to 7-day low but stays in ‘very poor’ zone

November, however, was slightly cooler than usual, as average monthly maximum temperature of 27.8 degrees Celsius was the lowest since 2013, when it was 27.3 degrees. The normal monthly maximum for the month is 28.2 degrees. Average minimum temperature was also slightly lower at 12.3 degrees compared with the normal 12.9 degrees.

All days except two saw AQI values exceeding 300, which means residents had no respite from the toxic blanket that smothered the capital through the month.

Last year, Delhi had light showers on November 17, and AQI dropped to a more breathable 171. In 2019, November saw the influence of a western disturbance towards the end of the month that provided some relief.

“Meteorological conditions, including wind speeds and mixing height, became increasingly unfavourable for dispersion of pollution as November progressed. Unlike November 2020, Delhi did not experience any rainfall in November this year,” said Tanushree Ganguly, programme lead at the Council on Energy, Environment and Water, a Delhi-based think tank. “Furthermore, this November was slightly cooler than last year, which suggests that emissions from local biomass burning for heating needs may have increased,”

This year, the peak pollution level for the month were recorded on November 12, when the AQI touched 471, while in 2016, the peak touched 497.

However, more air quality monitors could play a role in it, experts said. “The peak this year or that year may not be that different, since only nine stations were considered for the 2016 reading, while now, there are 36 to 38 stations in Delhi and the average reading gets impacted,” said Anumita Roy Chowdhury, executive director at the Centre for Science and Environment, an advocacy group. “Both can be equally dangerous,”

In contrast, October was the cleanest since 2015, with an average AQI of just 173, as a delayed monsoon kept pollution levels at bay.

Close Story

Less time to read?

Try Quickreads

  • Visuals from the site of the accident in Bihar’s Purnia. (HT Photo)

    Eight migrant labourers from Rajasthan crushed to death in Bihar road mishap

    At least eight migrant labourers were crushed to death, while six others were grievously injured, when an iron rod-loaded truck in which they were travelling met with a major accident on NH-57 on Monday morning. Confirming the deaths, sub-divisional police officer SK Saroj said the labourers, all residents of Rajasthan, were heading to Jammu from Siliguri in West Bengal when the driver lost control and toppled on the roadside.

  •  (PTI)

    Gusty winds uproot trees in Delhi, disrupt traffic

    The Delhi fire control room received at least 20 calls until 9 am on Monday related to the uprooting of trees and wall collapses because of the heavy rain and gusty winds. The calls were received from places such as Delhi Cantonment, Civil Lines, Main Rohtak Road, and Dhaula Khan. The rains and the gusty winds up to 70 km per hour also led to traffic jams in many parts of the city.

  • Police teams on bicycles are helping people in Gurugram who are stranded due to waterlogging. (ANI Photos)

    Gurugram rains: Waterlogging woes return; 2,500 cops deployed to manage traffic

    The traffic police advised people to avoid stretches such as Narsinghpur area, Jharsa Crossing, Sector 29, Sector 38, Sector 50, Rajeev Chowk, Sheetla Mata Road, Civil Lines, Golf Course Extension Road, Vatika Chowk, Sector 52 and Daulatabad Flyover. “We have deployed teams, and are pumping out water through motors to ensure smooth flow of traffic, but congestions are being reported from many areas,” Ravinder Kumar Tomar, deputy commissioner of police (traffic) said, warning commuters to plan their journeys accordingly.

  •  (HT PHOTO)

    Delhi faces power cuts amid rains, gusty winds

    New Delhi: The heavy rain and gusty winds uprooted trees and led to water logging in Delhi on Monday and triggered power cuts across the city. The India Meteorological Department said thunderstorms were expected to continue in the city accompanied by gusty winds with a speed of 60-90 kilometre per hour. Officials urged residents, especially children, to stay away from electricity poles, sub-stations, transformers, and streetlights.

  • Several parts of the national capital and the NCR received heavy rain with thunderstorms.

    Delhi rain brings May minimum temp to a decade-low, says private agency Skymet

    Delhi was much in need of a relief amid intense heatwave over the last few weeks and heavy rain and thunderstorms did just that. The mercury dropped by around 11 degrees Celsius in nearly 1.5 hours on Monday morning. “Today, between 5:40 am and 7 am, temperature fell by 11 degree Celsius, from 29 degree Celsius to 18 degree Celsius,” the India Meteorological Department said as per news agency ANI. Power blackouts were also reported.

Story Saved
Saved Articles
My Reads
Sign out
New Delhi 0C
Monday, May 23, 2022