Air pollution is the top culprit: there were 6.5 million deaths globally in 2015, and India's share is about 28%, or 1.81million.
"This is an immensely important piece of work highlighting the impact that environmental pollution has on death and disease", Maria Neira, the WHO director of public health and the environment, told the Guardian.
An estimated 9 million people died from pollution exposure in 2015, the commission reports.
But according to a new study published online Friday in The Lancet, a peer-reviewed medical journal, not only is pollution more harmful to global human health than we realize, our economic justification for it is also far off the mark. The figure of number of deaths due to air pollution, compiled by the Lancet study, is, in fact, over 7,00,000 more than what an another worldwide report, State of Global Air (SGA) 2017, had come out with earlier this year. The Lancet report, however, is based on data from the Global Burden of Disease study which analysed multiple parameters over two years to arrive at the figures. The polluted water would be linked to 1.8 million deaths, for example through poor sanitation or contamination of the sources, causes of gastro-intestinal diseases and parasitic infections.
Regardless of a nation's prosperity, deaths from diseases caused by pollution were most prevalent among minorities and the marginalised.
Researchers warned that nine million could be an underestimate of the true number of deaths due to pollution each year, as the link between pollution and certain diseases - like dementia or diabetes - is an area of emerging science. For instance, the study didn't take into account the effects of endocrine disruptors, pesticides, or flame retardants, all of which are widely used and known to contribute to premature death.
According to the study, #Environmental Pollution is killing at least 9 million people annually. "Pollution is killing people here and now; the big deaths from climate change will come in the next century". "They need to looked after", said one of the study's authors, Richard Fuller, who is head of the global pollution watchdog Pure Earth.
"People who are sick or dead can not contribute to the economy", he said, adding that sick people also often require the care of others, which adds additional cost.
Dr Penny Woods, chief executive of the British Lung Foundation, said: "This report reveals the consequences air pollution can have when left unchecked".
But going back on pollution regulation will only worsen the public health threats faced by residents of developing and developed countries. "We know that they harm", he said, "but there is not enough analysis to be able to say how they impact the entire globe".