At the current pace of urbanization, the world’s cities will add 65 million inhabitants a year between now and 2025. The resulting demand for infrastructure will mean that each year, India alone will need to add as much floor space as exists in all of Chicago, and China more than twice that. The way the world builds now will determine urban sustainability—in emissions, waste production, and water use—for decades.
In this article, we examine what could become the building blocks for the sustainable cities of the future: “green districts.” The term is new and still imprecise. Our definition of a green district is a densely populated and geographically cohesive area that is located within a city and employs technologies and design elements to reduce resource use and pollution.