Much the same is occurring in India. Already the world's fastest-growing economy, India will become the world's most populous nation (probably by 2022) and its biggest economy (possibly by 2048). It, too, runs on coal--with similar consequences. New Delhi, ringed by coal plants, is said to have the world's most polluted air, worse than anything in China. India's outdoor air pollution causes 645,000 premature deaths a year, according to a 2015 Nature study. Even in the United States, which uses less coal than other big nations, coal pollution leads to as many as 25,000 deaths per year.