Air pollution
About 76.8% of India’s population was exposed to mean PM2.5 more than 40μg/m³, which is the recommended limit set by the National Ambient Air Quality Standards of India.
PM is short for particulate matter. PM2.5 are fine particles invisible to the naked eye and can only be seen by using an electron microscope.
Delhi had the highest annual mean PM2.5 in 2017, followed by Uttar Pradesh, Bihar and Haryana, all of which had mean values of PM 2.5 greater than 125 μg/m³.
“Air pollution damages the health of every person living in India. Apart from causing lung diseases, cancers and cognitive loss, noxious air also damages blood vessels, causing strokes and heart attacks,” said Prof K Srinath Reddy, president, Public Health Foundation of India.
The disability-adjusted life years (DALYS, or healthy years lost due to disease, disability or early death) from ischaemic heart disease, stroke, chronic obstructive pulmonary disease and lung cancer attributable to air pollution were found to be similar to those attributable to tobacco use.
“These are conservative estimates as we have deliberately taken an approach where we use only those diseases and conditions (heart disease, lung diseases, diabetes) for which there is firm evidence in scientific literature. For example, air pollution is also linked with low birth weight and cognitive impairment, but since these are early studies and there is no conclusive evidence, we have not included them,” said Dandona.
Cleaning air would raise the average life expectancy across India by 1.7 years, with people living in the highly polluted northern states of Rajasthan, Uttar Pradesh and Haryana gaining more than two years.
“The intent of the study is to provide comprehensive data from each state that will be useful for policy makers. We did this using multiple satellite-based aerosol optical depth data and combined with a chemical transport model, which was then titrated with PM 2.5 data from ground level monitoring stations,” said Dandona.
“The study shows that even in places where pollution is low, it is exceeding norms during non-seasonal peaks, leading to cumulative exposure and sustained damage to the entire population. Action must be local, but policies have to address concerns of the entire population,” said Reddy.