Pollution was responsible for about 9 million deaths around the world in 2015, according to a new study commissioned by The Lancet. That's "three times more deaths than from AIDS, tuberculosis, and malaria combined and 15 times more than from all wars and other forms of violence," epidemiologist Philip Landrigan and his collaborators wrote.

Key findings from the research, which looked at causes of disease and premature death in 130 countries:

• In 2015, an estimated 6.5 million people died from heart disease, stroke, lung cancer and other respiratory conditions tied to air pollution. Water pollution was responsible for 1.8 million deaths.
• 92% of pollution-related deaths were seen in low-income and middle-income countries, per an accompanying article. The most deaths were in India (2.5 million) and China (1.8 million).
• Economic impact: The report estimated a 1.3% reduction in GDP in low-income countries versus 0.5% in developed ones. But "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," writes the AP's Katy Daigle.

"It doesn't have to [get worse]. It's not an inevitable outcome," Landrigan told the Washington Post. "Pollution control is a winnable battle."