Winter chill grips Delhi as air quality remains in ‘very poor’ category

New Delhi: As the chilling winter sets in, Delhi-NCR witnessed a slight drop in temperatures on Saturday, worsening the air quality. While people are struggling to step outdoors, the national capital recorded its lowest temperature of the season at 6.8°C.

According to the weather department, Delhi is expected to experience cold conditions over the coming days. On Saturday, the city was likely to see partly cloudy skies and winds of 15–20 km/hr. The minimum temperature on Sunday and Monday is expected to hover between 8–10°C, said the India Meteorological Department (IMD).

Air quality may show some improvement as stronger winds help disperse pollutants. On Saturday, Delhi recorded an AQI of 334 (very poor) at 10 am, while the AQI at 4 pm on Friday was 327 (very poor).

Earlier, the IMD had forecast isolated coldwave conditions in parts of northwest India until December 5 due to cold northwesterly winds blowing from snow-covered mountains to the plains. The minimum temperature of 5.7°C recorded on December 1 marked the coldest start to December since at least 2011. However, officials clarified that Friday did not qualify as a coldwave day.

A ‘coldwave’ is declared when the minimum temperature drops to 10°C or lower and is 4.5°C or more below normal, with at least two stations meeting this criterion for two consecutive days. On Friday, only one station — the Ridge — recorded a departure of more than 4.5°C below normal.

Typically, Delhi's minimum temperatures fall below 5°C in December, mostly in the latter half of the month. Last year, December 12 and 16 saw a minimum of 4.5°C, and 4.9°C was recorded on December 15, 2023. In previous years, the city recorded 5°C on December 26, 2022; 3.2°C on December 20, 2021; 3.1°C on December 31, 2020; and 2.4°C on December 28, 2019.

Experts say continuous western disturbances affecting the northern plains may slowly influence minimum temperatures. "Though feeble in nature, they will bring cloudiness, which will raise the minimum temperature marginally,” an official said.

According to the Central Pollution Control Board (CPCB) classifies air as "good". Id the AQI is 50 or lower; "satisfactory" between 51 and 100. It is considered to be "moderate" between 101 and 200; "poor" between 201 and 300; "very poor" between 301 and 400; and ‘severe’ when it exceeds 400.