Majority of the world's population breathes dirty air, report says

Most of the world has dirty air, with just 17% of cities globally meeting air pollution guidelines, a report Tuesday found. According to data from 40,000 air quality monitoring stations in 138 nations, the dirtiest air was found in Chad, Congo, Bangladesh, Pakistan, and India, according to the Swiss air quality monitoring database IQAir.

Six of the nine most polluted cities were in India, with Byrnihat, an industrial town in northeastern India, having the highest pollution.

Since many regions of the world lack the monitoring necessary for more precise statistics, experts warned the true level of air pollution may be far higher. For instance, there is just one monitoring station per 3.7 million inhabitants in Africa.