Delhi AQI "Very Poor" For 14th Day, Temperatures Likely To Drop From November 17

Delhi's air quality remained "very poor" for a 14th consecutive day on Tuesday, with an AQI reading of 334, as vehicular emission was the biggest contributor to the city's pollution, accounting for 15.4 per cent.

The Air Quality Index (AQI) has been in the "very poor" category since October 30, when it was recorded at 307.

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".

According to the Centre's Decision Support System for Air Quality Management, vehicular emissions will remain the top contributor to Delhi's pollution over the next two days, with an estimated share of approximately 10 per cent. On Tuesday, it was 15.5 per cent.

The national capital's 24-hour average AQI, recorded at 4 pm every day, stood at 334, down from 354 on Monday. Air pollution levels reached the "severe" category at one station in Anand Vihar.

Across the country, three stations registered "very poor" air quality, including Delhi, while one station in Bihar's Hajipur recorded the AQI in the "severe" category with a reading of 427.

Delhi recorded the fourth-worst air quality in the country, ranked behind Hajipur, Chandigarh (343) and Patna (340), according to the data.

Meanwhile, the prominent pollutants in Delhi on Tuesday were PM10, according to the Central Pollution Control Board (CPCB).

PM10 refers to a particulate matter that is 10 micrometre or less in diameter. These tiny solid or liquid particles suspended in the air can be inhaled into the lungs.

The sources of PM10 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 to it can also increase the risk of heart and lung diseases.

Apart from transportation, other contributors to Delhi's pollution include farm fires, though data was not available on the website of the Consortium for Research on Agroecosystem Monitoring and Modeling from Space, which tracks the number of stubble-burning incidents reported each day.

Priyanka Singh, programme lead at the Delhi-based independent think tank Council on Energy, Environment and Water (CEEW), said the AQI has consistently remained above 350 so far in November, except on November 10 and November 12, when it was 334 due to relatively higher wind speeds.

She said according to the Air Quality Early Warning System (AQEWS), the AQI is expected to stay around 350 for the next two days. After November 14, the AQI is anticipated to drop below 350, with a further decrease below 300 expected by November 19.

This improvement may be due to a reduction in the number of farm fires after November 15. Although the forecast is that the air quality will improve, citizens are advised to limit outdoor activities and take precautions, such as wearing masks, to reduce exposure, Singh added.

Meanwhile, the capital is experiencing unusually-high temperatures this November as the specific weather conditions that usually trigger the onset of winter are not aligning yet.

In mid-November, both the daytime and nighttime temperatures in Delhi remain well above seasonal norms.

As of the second week of the month, daily highs continue to hover above 30 degrees Celsius, while nighttime temperatures range between 16 degrees Celsius and 18 degrees Celsius -- a stark contrast to previous years, when the mercury would typically drop to between 10 degrees Celsius and 15 degrees Celsius by now.

Talking to PTI about the current weather pattern and the delayed onset of winter, an India Meteorological Department (IMD) official said, "Each year, a specific pattern of seasonal winds and temperature drops lead to the onset of winter. But this year, those conditions have not aligned yet." "The northern wind flow and western disturbances, which typically bring colder air, have not fully set in. However, we expect this trend to shift around November 17, after which temperatures are likely to start falling," he said.

A layer of morning smog is covering major parts of the capital, with chilly winds early in the morning and late in the evening bringing a winter bite to Delhi, where the temperature reached 32.8 degrees celsius on Tuesday, 4.3 notches above normal.

Humidity fluctuated between 64 per cent and 96 per cent during the day.

The weather office has forecast morning mist and shallow fog, followed by clear skies on Wednesday, with the minimum and maximum temperatures expected to hover around 16 degrees Celsius and 32 degrees Celsius respectively.

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