While Delhi recorded “very poor” air quality the morning after Diwali, it is, as per data, the least polluted Diwali that the city has seen in seven years and the Aam Aadmi Party-led government has credited the efforts of the people but said that there is still a long way to go.
Delhi Chief Minister Arvind Kejriwal on Tuesday said the results of efforts made by Delhi residents to curb pollution in the city are encouraging but there is still a long way to go.
His remarks came a day after Diwali when the Air Quality Index in the national capital stood at the ‘very poor’ category. The situation, however, was relatively better than previous years due to favourable meteorological conditions which diluted the effect of many residents flouting a firecracker ban and stubble burning.
Delhi environment minister Gopal Rai said there was 30 per cent less pollution on Diwali in Delhi as compared to last year. The air quality index (AQI) stood at 323 on Tuesday (the day after Diwali) as compared to 462 last year, he said.
Delhi Air Pollution Latest Updates:
-How Cyclone Sitrang Helped Improve Delhi’s Air Quality on Diwali
A change in the direction of Cyclone Sitrang on Sunday played a big role taming Diwali pollution over Delhi-NCR, and much of North India, resulting in clearer skies and relatively cleaner air quality the morning after Diwali as compared to the last few years, weather experts said.
Cyclone Sitrang crossed the Bangladesh coast on Monday. Since the system moved in a direction (north-northeasterly) away from the northern plains of India, it pulled winds and moisture towards it. This led to moderately strong westerly wind flows and dry conditions, both of which enabled dispersal of pollutants, a TOI report cited experts.
“A cyclone is a low-pressure system, with winds blowing towards the centre of the cyclone. When Sitrang moved towards Bangladesh, winds from north India moved in that direction. Therefore, it exacerbated the air flow in north India. It also drained out moisture from the region,” the report quoted India Meteorological Department chief Mrutyunjay Mohapatra as saying.
Mohapatra said that a deep trough in the mid and upper atmosphere over east Uttar Pradesh also reinforced the westerly wind flows in the region.
As per Centre’s air quality monitoring body SAFAR, Delhi and NCR saw west-moving winds at “moderate” speeds of 8-16kmph on Tuesday. Dry and westerly winds at moderate to high speeds usually help clear up pollution over North India. Under calmer conditions, however, these winds transport the pollution triggered by farm fires from Punjab and Haryana. High moisture in the air too raises pollution levels.
A cocktail of all these meteorological conditions played a crucial role played in either trapping or dispersing pollutants from sources such as Diwali fireworks or stubble-burning.
“Had the cyclone hit the Odisha coast and moved northwestwards towards Chhattisgarh, the situation in north India would have been very different. A cyclone moving towards the region would have led to an incursion of moist, easterly winds, which would have led to cloudy skies. Under such conditions, pollution levels may have shot up,” Mohapatra added.
-Thank Cyclone Sitrang Effect for Delhi’s Improved Post-Diwali Air Quality
While relatively lesser use of firecrackers after a ban helped, meteorological conditions played a big role in Delhi’s improved air quality on Diwali this year.
Experts attributed the improvement to weather conditions, particularly the effect of Cyclone Sitrang that crossed Bangladesh on Monday and warmer temperatures on account of Diwali coming relatively early this year.
Dry westerly winds at speeds of 4-10kmph on Monday night, and 8-16kmph on Tuesday, helped drain out pollutants from the region. The visibility during the day was recorded at 3,000-4,000 metres and officials of the weather department said such visibility a day after Diwali was “rare”.
“As expected, the combination of warmer climate, favourable meteorological conditions with higher wind speed, lesser stubble burning created conducive atmosphere and prevented trapping of smoke and pollutants,” TOI quoted Anumita Roychowdhury, executive director research and advocacy, Centre for Science and Environment, as saying,
-There Was 30% Less Pollution on Diwali in Delhi as Compared to Last Year: Gopal Rai
There was 30 per cent less pollution on Diwali in Delhi as compared to last year and the city recorded its best air quality for the day after the festival in several years, Environment Minister Gopal Rai said on Tuesday.
“People of Delhi were very thoughtful on Diwali this year and I want to thank them. Today, the pollution level is the lowest in five years,” Rai told reporters on the sidelines of an event where he launched 150 mobile anti-smog guns. He said the anti-smog guns will be deployed at 40 spots across the capital where air pollution is high.
The minister said that there has been a decline of 30 per cent in pollution level as compared to the previous year but added that the AQI is still worrying.. “The AQI of 323 is still worrying and tells us that air pollution will increase in the coming days,” he said. Rai further claimed the Punjab government controlled stubble burning in the state without support from the Centre.
“Punjab reported 1,019 incidents of stubble burning on Diwali day (Monday) as compared to 3,032 on Diwali last year. “On the other hand, farm fires have increased in Haryana and Uttar Pradesh,” he said.
-Still a Long Way to Go: CM Kejriwal on Delhi Pollution
Delhi Chief Minister Arvind Kejriwal on Tuesday said the results of efforts made by Delhi residents to curb pollution in the city are encouraging but there is still a long way to go. His remarks came a day after Diwali when the air quality in the national capital was recorded in the ‘very poor’ category. The situation, however, was relatively better than previous years due to favourable meteorological conditions which diluted the effect of many residents flouting a firecracker ban and stubble burning.
Delhi’s air quality index (AQI) stood at 326 at 8 am. “Delhiites are working hard in the field of pollution. There have been very encouraging results but there is still a long way to go. We will make Delhi the best city in the world,” Kejriwal said in a tweet in Hindi.
Emissions from firecrackers and farm fires have contributed significantly to Delhi’s PM2.5 pollution on Diwali over the years. Their share this year was relatively less than previous years due to reduced bursting of firecrackers and moderately warm and windier conditions which prevented rapid accumulation of pollutants.
Delhi had recorded an AQI of 382 on Diwali last year, 414 in 2020, 337 in 2019, 281 in 2018, 319 in 2017, and 431 in 2016, according to Central Pollution Control Board data. An AQI between zero and 50 is considered ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’, and 401 and 500 ‘severe’.
-Delhi Records ‘Very Poor’ AQI the Morning After Diwali
Delhi recorded “very poor” air quality on Tuesday, a day after Diwali, as residents flouted the ban on firecrackers in many parts of the capital on Diwali night, but the pollution levels for the next day were the lowest since 2015 thanks to favourable meteorological conditions that diluted the effect of the fireworks and stubble burning.
However, the neighbouring cities of Ghaziabad (266), Noida (299), Greater Noida (272), Gurugram (292) and Faridabad (289) reported “poor” air quality. An air quality index (AQI) between zero and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.
Delhi | Cleanest air during #Diwali time in last 7 years#AirPollution pic.twitter.com/2LQSvWIyWP
— Prasar Bharati News Services & Digital Platform (@PBNS_India) October 25, 2022
The firecracker emissions pushed the PM2.5 concentration at most places in the capital over 550 micrograms per cubic metre by 1 am. However, the PM2.5 levels dropped below 150 micrograms per cubic metre by 4 pm due to warm and windier conditions, which are favourable for the dispersion of pollutants. PM2.5 are fine particles that are 2.5 microns or less in diameter and can travel deep into the respiratory tract, reaching the lungs and entering the bloodstream.
Delhi recorded an AQI of 310 at 11 pm on Monday. It increased to 326 by 6 am on Tuesday, remained stable till 9 am and started decreasing thereafter. The 24-hour average AQI at 4 pm stood at 303, the lowest for the day after Diwali since 2015, when the Central Pollution Control Board (CPCB) started maintaining air quality data.
Delhi’s AQI on the day after Diwali stood at 360 in 2015, 445 in 2016, 403 in 2017, 390 in 2018, 368 in 2019, 435 in 2020 and 462 in 2021. Since Diwali was observed early in the season this year, moderately warm and windier conditions prevented rapid accumulation of pollutants from firecrackers bursting and reduced the effect of stubble burning.
(With PTI inputs)
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