The world is on track to add as many people to cities in the next 40 years as we have in the last 40 centuries. Those new buildings and roads will require a lot of concrete, which historically was an economically and environmentally inefficient building material. However, new innovators are leveraging technology to tackle both of those problems. The challenge they face, though, is around policy and building momentum. Right now, regulations prohibit some concrete manufacturers from innovating, even as more companies are demanding climate action.