Delhi’s air pollution lingered near the “severe” level for the third consecutive day on Tuesday, with the AQI reaching 373 amid the season’s first episode of fog.
The capital’s 24-hour average Air Quality Index (AQI), recorded at 4 pm each day, stood at 373 on Tuesday, down from 381 on Monday and 382 on Sunday.
Air pollution levels reached the “severe” category (AQI above 400) at eight stations across the city, down from 13 in the morning. These locations were Anand Vihar, Ashok Vihar, Bawana, Mundka, New Moti Nagar, Jahangirpuri, Wazirpur, and Vivek Vihar.
Elsewhere in the country, several locations recorded AQI levels in the “very poor” category.
Jhunjhunu had the worst air quality, with a reading of 376, followed by Delhi, which recorded the second-worst AQI on Tuesday, as it did on Monday.
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’, 401 and 450 severe’ and above 450 severe plus’.
The city also recorded its first fog of this winter season.
According to data, the first shallow fog last year appeared on October 31, while in 2022, it was on October 12.
An IMD official explained that factors like wind speed, humidity, low temperatures, and pollutants all contribute to fog formation near the surface. When the pollution level is already high, this fog becomes “smog,” as pollutants combine with moisture to reduce visibility.
This occurs because moisture in the air traps pollutants closer to the ground, and low temperatures with calm winds make it difficult for the pollutants to disperse.
Fog is classified into different types based on visibility levels: shallow fog is when visibility reduces to up to 500 meters, moderate fog up to 200 meters, dense fog up to 50 meters, and very dense fog when visibility is less than 50 meters.
Safdarjung visibility dropped to 800m with calm winds on Tuesday.
Meanwhile, the prominent pollutants in Delhi on Tuesday were PM 2.5 and PM 10, according to the Central Pollution Control Board.
PM 2.5 consists of fine particulate matter capable of penetrating deep into the respiratory system and triggering health problems.
Similarly, PM 10 refers to particulate matter that is 10 micrometers or less in diameter. These tiny solid or liquid particles suspended in the air can be inhaled into the lungs.
The sources of PM 10 include dust, pollen, mold, vehicle exhaust, and industrial emissions, which can cause respiratory problems as they penetrate deep into the lungs, potentially leading to issues such as asthma, bronchitis, and other respiratory diseases. Long-term exposure can also increase the risk of heart and lung diseases.
Vehicular emission was the biggest contributor to Delhi’s pollution on Tuesday, accounting for approximately 10.7 per cent, according to the Centre’s Decision Support System for Air Quality Management.
It is predicted that vehicular emissions will remain the top contributor to Delhi’s pollution over the next two days, with an estimated share of approximately 13 per cent.
Apart from transportation, other contributors to Delhi’s pollution include farm fires.
Data shows that on Monday, a total of 263 farm fires were recorded in Punjab, 13 in Haryana, and 84 in Uttar Pradesh.
On the issue of Delhi’s pollution, Abhishek Kar, Senior Programme Lead at the Council on Energy, Environment and Water, said the AQI is expected to remain consistently above 350 until November 10.
The major contributors to current air pollution are stubble burning, transportation, and dust. “Authorities need to strictly curb emissions at the source,” he said.
In addition to addressing stubble burning in the upwind states of Punjab and Haryana, there is a need for the strict implementation of GRAP Stage 2 measures, such as intensified inspections of dust control measures at construction sites and increased parking fees to discourage private vehicle usage, to control the surge in AQI, Kar added.
Weather experts say the temperature will remain the same and may not start dropping until the end of the second week of November.
All the same, a layer of morning smog is covering major parts of the capital, and chilly winds are bringing a winter bite to Delhi.
On Tuesday, the maximum temperature was recorded at 32.6 degrees Celsius, 2.1 notches above normal.
Humidity fluctuated between 67 and 94 per cent during the day.
The weather office has forecasted morning mist and clear skies during the day on Wednesday, with maximum and minimum temperatures expected to settle at 33 and 17 degrees Celsius.
