By admin 
Delhi was blanketed by a thick, gray haze on Thursday morning, which took about three hours to dissipate as the city’s residents, mostly children and the elderly, struggled with painful coughs and burning eyes – annual complaints for the capital in India. the winter season.
Poor visibility in Delhi and the National Capital Region on Thursday due to heavy air pollution. (Sunil Ghosh/HT Photo)
Moreover, a combination of low wind speeds, the presence of moisture in the air and a toxic cocktail of pollutants – from both local sources and neighboring states – left the capital’s air quality index (AQI) in the “very poor state” . ” zone at 377 – 25 points higher than the 352 recorded the previous day, and tethering close to “severe” levels.
At 10 p.m. the AQI was 383.
Forecasts show that unfavorable meteorological conditions are likely to persist in the coming days, with the capital’s pollution levels likely to remain in the ‘very poor’ category until at least the weekend.
The Central Pollution Control Board (CPCB) classifies an air quality index (AQI) between 0 and 50 as “good”, between 51 and 100 as “satisfactory”, between 101 and 200 as “moderate”, between 201 and 300 as “poor”, between 301 and 400 as “very poor”, and over 400 as “severe”.
Winds remained calm throughout the day and failed to disperse pollutants, while moisture levels fluctuated between 59% and 94% over a 24-hour period, although remaining below 75% for most of the day. At the same time, haze in the morning hours caused Delhi’s visibility to drop to 800 meters for the third day in a row.
Meteorological experts said with pollution levels quite high and moisture levels below 75%, the haze was likely smog – not fog – for most of the day.
“For the past three to four days, pollution levels have been high and relative humidity has largely remained below 75%. In weather terminology, we call it fog when visibility drops below 1,000 meters and although there is some moisture in the air, pollutants are currently the dominant factor when it comes to poor visibility. It is safer to say that we are recording smog even though there is no official definition of the term,” said Mahesh Palawat, vice president at Skymet meteorology.
Separately, India Meteorological Department (IMD) Director General M Mohapatra said the Met has used both terms – smog and fog – in their forecasts for Delhi. “For fog, visibility should be lower than 1,000 meters, but if humidity is lower than 75%, smog may occur because humidity is low,” he said.
IMD data showed that the wind direction over Delhi has also remained variable over the past three days, fluctuating between northwesterly, easterly and southeasterly. The winds at higher levels, which blow at a height of 1 km and more above the surface, are predominantly from the northwest, allowing stubble smoke from the northern states to reach the capital.
“It (the haze) is a combination of local pollutants and stubble smoke. Since the wind is calm at the surface, this is more visible and does not spread,” Palawat added.
CPCB data on Thursday showed that both PM 2.5 and PM 10 were dominant pollutants at 4 p.m. Of the 40 AQI stations in Delhi, twelve were in the severe range at the time – at 435, Wazirpur was the highest, followed by Anand Vihar and Jahangirpuri (both 434).
Meanwhile, Delhi recorded another warm day on Thursday as the maximum temperature in the city stood at 31.7 degrees Celsius (°C) – two degrees above normal for this time of the year, but 0.6 degrees lower than Wednesday. The low was 18°C, four degrees above normal and 0.7°C higher than the previous day’s low of 17.1°C.
According to forecasts, maximum and minimum temperatures are likely to hover around 33°C and 18°C on Friday.