The next big thing in sustainable product design is circular economy principles integrated into the built environment. The built environment, as opposed to the natural environment, encompasses the environment that humans have built for residential, commercial, transportation, etc. purposes. There has been a lot of development in sustainable design in the built environment in recent years, especially in urban city design. Arup, an international engineering company, helps cities accelerate decarbonization and move towards climate resilience by providing design services that incorporate renewable energy, efficient energy grids, and design for reuse.