March 11 (UPI) -- Fewer than one in five global cities met World Health Organization air pollution standards in 2024 with Central and South Asia accounting for the nine most polluted metropolitan areas on Earth, six of which were in India, a new report out Tuesday shows. Byrnihat, straddling the border between the Meghalaya and Assam states of northeastern India was the most polluted city with an annual average concentration of tiny, breathable so-called PM2.5 particulates of 128.2 micrograms