The IQAir World Air Quality Report, which analysed data from over 40,000 air quality monitoring stations across 8,954 locations in 138 countries, found that only 17 per cent of cities met the World Health Organisation’s (WHO) annual PM2.5 guideline of 5 micrograms per cubic metre (µg/m³).

BENGALURU, India (AP) — Most of the world has dirty air, with just 17% of cities globally meeting air pollution guidelines, a report Tuesday found.