Brunei and Sweden had the lowest numbers of pollution-related deaths.
Nearly 92 percent of pollution-related deaths occur in poor or middle-income countries, the study finds.
The alarm was sounded in Thursday's report by The Lancet Commission on Pollution and Health, an worldwide group of over 40 authors writing on health and environment. Of any single country, India bears the brunt with 2.5 million people killed by pollution in 2015, followed by China with 1.8 million. Based largely on 2015 data from the Global Burden of Disease, the report estimates that at least 9 million premature deaths were caused during the year by diseases from toxic exposure.More news: Britain reports hate crimes spike after Brexit vote, attacks
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The next largest risk factor, water pollution, accounted for 1.8 million deaths, while pollution in the workplace was linked to 800,000 deaths globally.
Most of these deaths were caused by non-infectious diseases linked to pollution, such as heart disease, stroke and lung cancer. In industrialized countries, such as India, Pakistan, China, Bangladesh, and Madagascar, air pollution contributes to a quarter of total deaths. Last year, crackers, vehicular pollution, emissions from coal plants, and burning of crop stubble in Punjab and Haryana also had created a blanket of smog that lingered for days forcing the Supreme Court, to ban the sale of firecrackers in the national capital region.