- The IQAir Air Visual 2018 World Air Quality Report by Greenpeace South East Asia has ranked Delhi as the world’s most polluted capital. In 2018, Delhi had an average yearly PM2.5 concentration at 113.5 micrograms per cubic metre.
- Dhaka (Bangladesh) was ranked the second-most polluted capital at 97.1 micrograms per cubic metre followed by Kabul (Afghanistan) with 61.8 micrograms per cubic metre.
- However, the city-wise rankings differ. In city-wise ranking, Gurugram ranked first with an annual average PM2.5 reading of 135.8 micrograms per cubic meter followed by Ghaziabad, followed by Faridabad, Faisalabad (Pakistan), Bhiwadi and Noida. Delhi ranked 11th.
- According to the National Ambient Air Quality Standards, the annual permissible limit for PM2.5 is 40ug/m3. The annual permissible limits prescribed by the World Health Organization are even lower at 10ug/m3. National Ambient Air Quality Standards are the standards for ambient air quality set by the Central Pollution Control Board (CPCB). Ambient air quality refers to the condition/ quality of outdoor air.
