A new study says roads made from steel slag, a waste product of steelmaking, could cut pollution & save lives. Mixed into an epoxy asphalt, the slag creates a surface that lasts about 15 years instead of six. Longer-lasting roads mean fewer repairs, less congestion & lower fuel use by vehicles. Across China's urban roads, the researchers estimate savings of 1.74 billion metric tons of CO₂-equivalent & up to 128,980 avoided premature deaths from cleaner air. The material costs more upfront & needs a week to cure.