Environmental pollution - from filthy air to contaminated water - is killing more people every year than all war and violence in the world. Pollution causes more deaths than smoking, hunger or natural disasters; more than AIDS, tuberculosis and malaria combined, according to a major study released on Thursday in The Lancet medical journal.
And the greatest numbers of deaths linked to pollution in 2015 year were in India with 2.5 million dying due to air pollution and another 0.64 million due to water pollution, says the study released on Diwali – India's festival of lights, and of course, polluting firecrackers.
Indian was followed by China with 1.8 million pollution-related deaths. Other countries including Bangladesh, Pakistan, North Korea, South Sudan and Haiti also see nearly a fifth of their premature deaths caused by pollution.
One out of every six premature deaths in the world in 2015 - about 9 million - could be attributed to disease from toxic exposure, the study says.
The financial cost from pollution-related death, sickness and welfare is massive, costing some $4.6 trillion in annual losses - or about 6.2 per cent of the global economy.
"There's been a lot of study of pollution, but it's never received the resources or level of attention as, say, AIDS or climate change," said epidemiologist Philip Landrigan, dean of global health at the Icahn School of Medicine at Mount Sinai, New York, and the lead author on the report.
The report marks the first attempt to pull together data on disease and death caused by all forms of pollution combined.
"Pollution is a massive problem that people aren't seeing because they're looking at scattered bits of it," Landrigan said.
The study found pollution was linked to around nine million deaths in 2015.
Dirty air - caused by everything from transport and industry to indoor fires - was the biggest contributor linked to 6.5 million deaths, it said. The next biggest was polluted water that spread gastrointestinal diseases and parasitic infections and killed 1.8 million people.
Areas like Sub-Saharan Africa have yet to even set up air pollution monitoring systems. Soil pollution has received scant attention. And there are still plenty of potential toxins still being ignored, with less than half of the 5,000 new chemicals widely dispersed throughout the environment since 1950 having been tested for safety or toxicity.
To reach its figures, the study's authors used methods outlined by the US Environmental Protection Agency for assessing field data from soil tests, as well as with air and water pollution data from the Global Burden of Disease, an ongoing study run by institutions including the World Health Organization and the Institute for Health Metrics and Evaluation at the University of Washington.
Even the conservative estimate of 9 million pollution-related deaths is one-and-a-half times higher than the number of people killed by smoking, three times the number killed by AIDS, tuberculosis and malaria combined, more than six times the number killed in road accidents, and 15 times the number killed in war or other forms of violence, according to GBD tallies.
It is most often the world's poorest who suffer. The vast majority of pollution-related deaths - 92 per cent - occur in low- or middle-income developing countries, where policy makers are chiefly concerned with developing their economies, lifting people out of poverty and building basic infrastructure, the study found. Environmental regulations in those countries tend to be weaker, and industries lean on outdated technologies and dirtier fuels.
In wealthier countries where overall pollution is not as rampant, it is still the poorest communities that are more often exposed, the report says.
"What people don't realise is that pollution does damage to economies. People who are sick or dead cannot contribute to the economy. They need to be looked after," said Richard Fuller, head of the global toxic watchdog Pure Earth and one of the 47 scientists, policy makers and public health experts who contributed to the 51-page report.
"There is this myth that finance ministers still live by, that you have to let industry pollute or else you won't develop,'' he said. "It just isn't true."
The report cites EPA research showing that the US has gained some $30 in benefits for every dollar spent on controlling air pollution since 1970, when Congress enacted the Clean Air Act, one of the world's most ambitious environmental laws.
Removing lead from gasoline has earned the US economy another $6 trillion cumulatively since 1980, according to studies by the US Centers for Disease Control and Prevention.
Some experts cautioned, however, that the report's economic message was murky. Reducing the pollution quantified in the report might impact production, and so would not likely translate into gains equal to the $4.6 trillion in economic losses.
While there has never been an international declaration on pollution, the topic is gaining
The World Bank in April declared that reducing pollution, in all forms, would now be a global priority. And in December, the United Nations will host its first-ever conference on the topic of pollution.
"The relationship between pollution and poverty is very clear," said Ernesto Sanchez-Triana, lead environmental specialist at the World Bank. "And controlling pollution would help us address many other problems, from climate change to malnutrition. The linkages can't be ignored."