Yale Environment 360: A federal program that has cleaned up or removed 50,000 high-polluting diesel engines from U.S. roads is scheduled to be cut by 70 percent under President Barack Obamas latest budget. The program eliminated 230,000 tons of soot and smog-causing pollutants, slashed more than two million tons of carbon dioxide emissions, and saved 205 million gallons of fuel. But the programs budget has faced steady cuts in recent years, falling from $50 million in fiscal year 2011, to $20 million in 2013, to a proposed...