Delhi has achieved its cleanest December air quality since the AQI system was established in 2015, with an average Air Quality Index (AQI) of 294.
Officials stated that this enhancement is due to robust, steady winds during the initial part of the month and unprecedented rainfall in the latter half.
As per information released by the Central Pollution Control Board (CPCB), December recorded the cleanest first half in Delhi’s history, featuring just one ‘very poor’ air quality day between December 1 and December 15.
On Monday, the AQI was measured at 173, placing it in the “moderate” range, which is a notable enhancement from the 225 (poor) recorded on Sunday. This was the eighth day of moderate air quality this month, whereas the capital had previously noted a maximum of three moderate days in December.
The month’s lowest AQI was noted on December 28, reaching 139, which signifies the cleanest December day ever recorded.
The average AQI for this period was 238, much lower than the typical AQI exceeding 300 for this season.
In contrast, Delhi’s average AQI was 348 in December last year, 319 in 2022, and 336 in 2021. The former lowest December AQI, recorded in 2015, was 300.
Furthermore, the month is projected to end with at least 53.5 mm of precipitation, ranking it as the fifth-wettest December since 1901. The city also noted its greatest single-day December precipitation in 101 years, recording 41.2 mm on December 28 (Friday).
This year, Delhi saw six rainy days in December, while there was only one in 2023, none in 2022, four in 2021, and one rainy day in December 2020.
Delhi had a total of 53.5 mm of rainfall this month, with 41.2 mm falling on one day alone. In contrast, December 2023 and 2022 experienced no precipitation, whereas 2021 noted 9.6 mm, and 2020 noted 1.6 mm.
As per the India Meteorological Department (IMD), the record for the highest single-day rainfall in December is 75.7 mm, which was observed on December 3, 1923.
Although the nights were pleasant, with an average minimum temperature of 8.4 degrees Celsius, aligning with the long-period average (LPA) for December, the daytime temperatures were a bit higher, with an average maximum temperature of 23.1 degrees Celsius—0.3 degrees above the LPA.
According to IMD officials, this is the coldest December since 2021, when the average high temperature reached 22.4 degrees Celsius.
Specialists credited the positive air quality in December to the beneficial spread of pollutants, especially during the initial two weeks of the month.
