Air pollution is now the world’s fourth-leading fatal health risk, causing one in ten deaths in 2013. According to a new study by the World Bank, the premature deaths due to air pollution costs the global economy about $225 billion in lost labor e, or about $5.11 trillion in welfare losses worldwide. That is about the size of the gross domestic product of India, Canada, and bined, notes the report

While we tend to think of air pollution as occurring in the urban areas of the developed world, most of the deaths are due to poor air quality in rural and underdeveloped regions:

Billions of people around the world continue to depend on burning solid fuels such as wood, charcoal, coal, and dung in their homes for cooking and heating. Consequently, the health risk posed by air pollution is the greatest in developing countries. In 2013 about 93 percent of deaths and nonfatal illnesses attributed to air pollution worldwide occurred in these countries, where 90 percent of the population was exposed to dangerous levels of air pollution. Children under age 5 in e countries are more than 60times as likely to die from exposure to air pollution as children in e countries.

While the monetary cost of air pollution is shocking, it’s likely even more than is estimated in the report. “The figure could be very much more if it included health costs,” said Urvashi Narain, lead author and senior environmental economist for the World Bank. “We did not include the costs of [morbidity] illnesses caused by pollution.”

“The scale of the problem is truly daunting,” added Narain. “The poor are more likely to live in polluted areas and are less able to access healthcare.”

These economic costs of air pollution have also increased significantly over time, claimsthe report. Between 1990 and 2013, total welfare losses due to premature mortality from exposure to air pollution increased by 94 percent. Damages from exposure to ambient air pollution also rose by 63 percent between 1990 and 2013, to $3.552 trillion, while damages from household air pollution from cooking with solid fuels rose by 287 percent, to $1.516 trillion.