NEW DELHI: Strong surface winds slightly improved Delhi's air quality on Saturday but it remained in the 'severe' category as the contribution of farm fires in the city's PM2.5 pollution reached the season's highest of 41 per cent, officials said.
According to the Central Pollution Control Board (CPCB) bulletin, the city's air quality index (AQI) stood at 449 (severe) at 8 am, and 437 at 4 pm.
The AQI on Friday was recorded at 462.
The CPCB's Sameer app showed that the AQI at Punjabi Bagh was 452, ITO 443, Chandni Chowk 445, Ashok Vihar 450, Karni Singh Shooting Range 470, Mathura Road 446, IGI Airport (T3) 426, NSIT Dwarka 429 and Patparganj 452.
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'.
The weather office said that strong surface winds will keep sweeping through the Delhi-NCR on Sunday as well and are expected to flush out pollutants.
The Ministry of Earth Sciences' air quality forecast agency, SAFAR, stated that stubble burning accounted for 41 per cent of Delhi's PM2.5 pollution on Saturday, the season's highest so far.
"Delhi's AQI is likely to improve to the upper end of the 'very poor' category as surface winds are becoming stronger, dispersing air pollutants. Strong north westerly winds enhance transport of emissions from stubble burning. Share of crop residue burning emissions in PM2.5 is 41 per cent (effective fire count 5,159)," SAFAR said on Saturday.
The weather office said the wind speed at both airports (IGI Palam and Safdarjung) were recorded between 10 and 15 kmph till 4pm.
Weather experts said due to rampant bursting of crackers on Diwali despite restrictions, the city's air quality after the festival dropped to its poorest level in five years.
Rise in incidents of stubble burning in neighbouring states also contributed towards it.
Air quality degraded to the 'severe' zone in the Delhi-NCR due to unfavourable weather conditions, low temperature and low mixing height and a poisonous cocktail of emissions from firecrackers, stubble burning and local sources, they added.
On Saturday, Delhi's maximum temperature settled at 28.
1 degrees Celsius, a notch below the season's average, and the minimum temperature was recorded at 14.
7 degrees Celsius, normal for this time of the year, the India Meteorological Department (IMD) said.
The minimum and maximum temperatures on Sunday are likely to hover around 15 and 28 degrees Celsius respectively, it added.
Weather scientists said the fog or smog condition has improved in the Delhi-NCR as forecasted.
In the morning, there was shallow fog in the city and visibility remained in the 600 to 800 metre range, reported at Delhi's two airports from 5.30 am to 9.30 am, the weather office said.
Visibility improved to 800 to 1,200m later in the day.
Meanwwhile, Dr Ashok Seth, Chairman, Fortis Escorts Heart Institute on Friday said the pollution levels are dangerous for the elderly people as well as COVID recovered patients.
Speaking to ANI, Dr Seth said, "These are really dangerous levels. AQI (Air Quality Index) levels are especially dangerous for the elderly and those with lung problems and heart disease. Pollution itself leads to chest congestion and bronchospasm. Those with Asthma, bronchitis will start getting worse. It itself predisposes to further chest infections, viral infections and cases of pneumonia. We see a lot of these happening when pollution rises.
"So elderly are at the biggest risk. Also, pollution is to be known for the inflammation of the heart arteries. This results in the precipitation of blood clotting leading to increased heart attacks and worsening of Angina," he added.
Asked about the effect of air pollution to COVID recovered patients, Dr Seth said, "People who recovered from COVID are vulnerable to this (air pollution). Of this group, a lot of them got residue lung problems from minor to major. The toxic gases and particles affect the lungs directly."
COVID recovered patients, too, are vulnerable. This is the time for the elderly to stay indoors, be flu-vaccinated and use air purifiers at home continuously."
The air quality in the national capital reached the 'hazardous' category on Friday morning, following the festival of Diwali. The concentrations of Pollution Meter (PM) 2.5 stood at 655.07 in Janpath on Friday morning.
As a thick blanket of smog shrouds the skies of Delhi, several people complained of itchy throat and watery eyes.
Despite the Delhi government's ban on firecrackers, several people were seen bursting crackers on street on the occasion of Diwali, contributing to the degradation of the air quality, amid increased contribution from farm fires.
(With ANI Inputs)