As Indian cities slip into that unfathomable vortex of air pollution, comes another shocker: 100 per cent Indians are exposed to PM 2.5 air pollutants in excess of the value specified by the World Health Organization (WHO) air quality guidelines, according to a report by The World Bank. PM 2.5 or particulate matter 2.5 are tiny particles with diameters of 2.5 micrometres or less, which can reach deep into the lungs and enter the blood circulation system. Exposure to these particles triggers asthma, lung irritation and coughing while in the long-term, it can cause lung cancer.
— source downtoearth.org.in 2017-10-29