New Delhi, India is the most polluted city in the world, according to 2014 findings from the World Health Organization (WHO). Air pollution is generally measured by concentrations of Particle Matter 2.5 (PM 2.5), which refers to matter in the air that is less than 2.5 micrometers in diameter, or the size that is small enough to be ingested the most deeply into the lungs. May 2014 PM 2.5 readings measured concentrations of PM that was greater than 350 micrograms per cubic meter of air, making it the worst in the world. This is thought to be due to the high concentration of coal-fueled factories, increasing number of cars, and lack of government regulations regarding pollution emissions.
More about most polluted cities:
In 2012, air pollution was thought to contribute to the deaths of over seven million people worldwide, according to WHO.
While Beijing, China’s air pollution is so bad it can be seen from space, its air pollution levels are three times less than New Delhi.
In addition to New Delhi being the most polluted city, India is also home to world’s top four polluted cities: Patna, Gwalior, and Raipur.