Over 90 percent of the world’s population breathed unhealthy air in 2015.

That’s one of many startling findings in the new State of Global Air report, released Tuesday by the Boston-based Health Effect Institute. Air pollution contributed to more than 4.2 million early deaths worldwide in 2015, making it the fifth-highest contributor to death, and was directly responsible for 7.6 percent of all global deaths.

Health Effects Institute

Most of this pollution comes not from the United States, but from rapidly industrializing countries like China and India. In fact, the study showed India registering a 50 percent increase in premature deaths from air pollution since 1990.

Health Effects Institute

The study said America’s relatively good air quality reflects “the impact of air quality management programs”—in other words, effective environmental policy. Meanwhile, Republicans in Congress this week are looking into “modernizing” many longstanding federal environmental laws, including the Clean Air Act. That’s GOP-speak for “weakening.”