Delhi AQI stays 'very poor', likely to worsen this week: What's behind the air quality drop?

DElhi’s send lineament remained ‘ rattling poor’ on mon as weak winds trapped pollutants, transcription an overall Air Quality Index (AQI) of 324 at 6:05 am, according to data from the Sameer app developed by the Central Pollution Control Board (CPCB).On Sunday as well, the national capital’s AQI remained in the ‘very poor’ category, recording an overall AQI of 366. Three monitoring stations also recorded "severe" air quality above 400, as per data from the CPCB.ALSO READ | Priyanka Gandhi calls on Modi, Delhi CM to 'clear filthy smog' in Delhi: ‘We will support and cooperate…’Delhi AQI todayThe data also showed that most of the total 39 monitoring stations recorded AQI above 300, falling into the ‘very poor’ category. These included Anand Vihar (371), Bawana (371), Burari Crossing (384), Jawaharlal Nehru Stadium (331), Mundka (343), Narela (386), Rohini (363) and Wazirpur (389).Many of the neighbouring cities in the National Capital Region (NCR) also recorded ‘very poor’ air quality, including Noida (311), Ghaziabad (334) and Gurugram (304).An AQI between 0 and 50 is considered "good", 51-100 "satisfactory", 101-200 "moderate", 201-300 "poor", 301-400 "very poor" and 401-500 "severe", according to the CPCB standards.ALSO READ | Delhi founder opens door, indoor AQI spikes from 97 to 500 within a minute: ‘Life has become hell in NCR’ While Delhi has not officially recorded a ‘severe’ air day so far this year, it is expected to so this week. The last such reading was on December 23, 2024, when the AQI was recorded at 406, as mentioned in an earlier HT report.On Sunday, at least five individual active ambient air quality stations at a particular time recorded AQIs in the ‘severe’ category.What is causing the AQI spike?According to the Air Quality Early Warning System (AQEWS) for Delhi, wind speed fell below eight kmph from the northwest during the evening and night hours on Sunday, which has reduced the dispersion of pollutants in the air.This can lead to breathing issues for many, especially people with lung or heart diseases, children and the elderly.The AQEWS also said that the air quality in the national capital is expected to remain in the “very poor” category till November 4.On Sunday evening, the PM2.5 level was recorded at 189.6 micrograms per cubic metre, while PM10 stood at 316, according to the CPCB data. Notably, PM2.5 refers to fine particles that are 2.5 micrometres or smaller in size, while PM10 includes larger particles up to 10 micrometres in diameter.Mahesh Palawat, vice president at Skymet meteorology said atmospheric conditions were unfavourable for dispersion of pollutants, leading to gradual accumulation, according to the earlier HT report. “Winds picked up – touching around 10 km/hr during the day on Sunday, which led to an improvement in the AQI. Otherwise, we were mostly seeing calm winds,” he was quoted as sayingHe said that the wind direction was variable through the day, barring the afternoon period, when it switches to westerly and northwesterly, favourable for transport of stubble smoke to Delhi.