The cost of air pollution is enormous. A study published in the prestigious medical journal, The Lancet, estimates that air pollution killed 1.24m Indians in 2017. The biggest cause of this calamity are fine particles - atmospheric particulate matter (PM) that have a diameter of less than 2.5 micrometers. They are so small that they are involuntarily inhaled deep into the lungs, leading to heart and lung disease. These fine particles are constantly produced by vehicle engine exhaust, factories, building sites, the burning of waste and by thermal power plants – more than half of India’s electricity is still generated by burning coal.
The 10 most polluted cities in the world are all in northern India, where air pollution is difficult to disperse due to the Himalayas forming a barrier to the north, preventing poor air from dissipating. On the top of the list is the city of Kanpur, the industrial hub of the state of Uttar Pradesh. In Kanpur, the coal burned by industry, emissions from vehicles, and the use of chemicals in hundreds of leather tanneries, is producing a toxic cocktail of airborne pollution.