For the first time ever, more than half of the world’s population is living in cities. However, only 12% of these people are exposed to levels of airborne particle pollution that meet the World Health Organisation (WHO) guidelines, these cities can be found in Canada and Iceland. Meanwhile, half of the planet’s mega-cities and their inhabitants have exposed to air pollution 2.5 times the WHO guidelines, with many places getting worse rather than improving. Over the past century and a half, carbon dioxide emissions have risen, and there are reports that more than 200 million people have become ill as a direct result of air pollution. In 2012 alone, it’s thought 3.7 million people died prematurely due to air pollution.
Whether it’s in Europe, North America, Africa or Asia, air pollution can have many devastating effects ranging from acid rain to heart disease. In an attempt to combat these issues by raising awareness, WHO studied more than 1,600 cities between 2008 and 2013 to compile a list of the world’s dirtiest cities. Mercer also compiles a Health And Sanitation list annually, which ranks every city in the world according to their cleanliness.
Like most cities on this list, Delhi has become synonymous with smog due to industry and traffic, which have combined to create incredibly high levels of particulate matter including carbon, nitrogen, sulphur and metal compounds.