In Canada, A new study has found that levels of air pollution downwind of the largest tar sands, oil and gas producing region in Canada rival levels found in the world’s most polluted cities. And that pollution could be tied to increased incidence of blood cancers in men that live in the area.

Fort Saskatchewan, Alberta, area tests showed levels of chemical pollutants to be between 300 and 600 times normal levels, and comparable to Mexico City in the 1990s when it was the most polluted city in the world.

Study co-author Stuart Batterman, a University of Michigan Professor of Environmental Health Sciences, indicated that the levels recorded “are evidence of major regulatory gaps in monitoring and controlling such emissions and in public health surveillance.”