Indian cities don’t get as much attention as Chinese cities do with respect to air pollution, said Anmol Vanamali, a senior fellow at the Worldwatch Institute. Yet, it is clear that Indian cities are just as, if not more, polluted.
According to the World Health Organization's data from 2014, Delhi was ranked as having the highest PM 2.5 levels in the world. Smaller than 2.5 microns in width, PM 2.5 particles are particularly dangerous to human health because they are small enough that they can lodge into a person's lungs. This specific type of pollution has been linked to premature death in people with heart or lung disease and to heart attacks.
n the year 2012, ambient air pollution was responsible for 3.7 million deaths, representing 6.7% of the total deaths. Worldwide, ambient air pollution is estimated to cause about 16% of the lung cancer deaths, 11% of chronic obstructive pulmonary disease (COPD) deaths, more than 20% of ischaemic heart disease and stroke, and about 13% of respiratory infection deaths.