The World Health Organisation has warned that over 80 percent of people in urban areas around the world are exposed to dangerous levels of air pollution with risk greater in lower and middle-income countries. Air pollution is the greatest environmental risk to health with three million people dying prematurely every year.
The highest levels of small and fine particulate pollution (PM10 and PM2.5) were recorded in South-East Asia and the Mediterranean. According to the WHO, Onitsha in Nigeria
has the highest levels of PM10 worldwide, followed by Peshawar in Pakistan and Zabol in Iran. The level of PM10 in Onitsha is nearly 30 times the recommended level.