Delhi’s air quality improves to ‘very poor’ category

Delhi’s air quality improved from the “severe” to “very poor” category on Wednesday even as dense fog continued to blanket the region and disrupted flight and train services.

The visibility at the Delhi airport dropped to 50 metres at 7:30am. No diversions were reported but several flights were delayed. At least 26 trains were running late by an hour or more, the northern railway said.

A minimum temperature of 5.9°C degrees was recorded at Safdarjung, the representational weather station. It was 2°C below normal. On Tuesday, a minimum of 6.4°C was recorded as cold wave conditions abated.

A cold wave is declared in the region when the minimum temperature is 4.5°C or more below the normal, or when it drops to 4°C or lower. Safdarjung recorded five consecutive cold wave days from January 5 till January 9, making it the longest for January since five such days were recorded in January 2013.

This was Delhi’s third worst cold spell between the years 2000 and 2023 for January due to a combination of consecutive cold wave days and low minimum temperatures.

“If we look at both the minimum temperatures and the number of consecutive cold wave days being recorded, then for January, this is the third coldest spell from 2000 onwards. It was most intense in 2006 when the minimum fell to as low as 0.2°C…a low of 1.4°C was also recorded. This spell lasted four days. In 2013, a minimum of 1.9°C was recorded with the spell lasting six consecutive days,” said India Meteorological Department scientist RK Jenamani.

He said another spell of cold with expected after January 14 when the wind direction returns northwesterly. “After a western disturbance departs on January 13, there will be cold winds again and the minimum will once again dip below 4°C…”

There was also the possibility of very light rain and drizzle on Thursday while the city was expected a record a maximum temperature of around 20°C on Tuesday, compared to 18.7°C on Tuesday.

Delhi’s AQI improved to 319 (very poor) at 8am on Wednesday thanks to an increase in wind speed, temperature, and mixing height. It recorded two consecutive “severe” air days on Monday (434) and Tuesday when the AQI touched 407.