However, the crown has been lost after Central Pollution Control Board (CPCB) revealed its data for September 2015 and January 2016.
While Delhi’s air pollution levels are far from being healthy, it still doesn’t stand in the category of being the worst in the country.
In its report, CPCB has published AQI for 24 cities comparing the pollution levels in various cities in the country. The air quality indices in India are determined by PM2.5 (fine, respirable particles), nitrogen dioxide (NO2), sulphur dioxide (SO2), and carbon monoxide (CO).
While Delhi scored a 362 (very poor) in January, Muzaffarpur in Bihar and Varanasi in Uttar Pradesh recorded AQI values of 409 (severe). During the same time, Faridabad stood at a 399. The only three cities with moderate air quality were Bengaluru, Panchkula and Haldia.
Bengaluru has earned the top spot when it comes to having the cleanest air in the country. The report also explains that the air quality in North India is about two to three times worse than that in the South Indian cities.
According to CPCB, while Delhi recorded 13 severe quality days between September 2015 and January 2016, Muzaffarpur observed 37, Varanasi had 24, Agra 22, and Lucknow 18. However, Delhi did have 69 very poor air quality days as compared to 43 in Varanasi and 43 in Kanpur.
The Indo-Gangetic plains cities have the worst AQIs. This reveals that as much as emissions are responsible for pollution, weather conditions and location also play a significant role. The areas where dry northerly winds converge with moist and humid southwesterly winds, condensation, takes place.
Condensation nuclei attract dust and smoke particles which remain suspended near the earth’s surface for a longer period. Thus, in the absence of strong northerly winds which abate these particles, pollution levels increase.
Image Credit: