India was the world's eighth most polluted country in 2022, dropping from fifth place the previous year. While the PM 2.5 level has dipped to 53.3 micrograms/cubic metre, that is still over 10 times the World Health Organisation's safe limit. The ranking was decided by Swiss firm IQAir in its 'World Air Quality Report' released on Tuesday. It is based on the level of PM 2.5, a pollutant closely tracked by scientists and health experts.