China—the world’s fastest-growing economy with the largest population—leads the world in cement production, the critical ingredient that has built China’s mammoth cities, sprawling roads, and other infrastructure. China pours 60 percent of the world’s cement; the country’s production in 2011-2013 surpassed U.S. production for the entire 20th century. While it paved the way for Chinese growth, it came at a dangerous cost: 1.6 million Chinese citizens die each year from respiratory illnesses linked to small particulate matter emissions, of which 27 percent come from cement production.