Nuclear science is helping cities address everyday challenges, from heating homes and securing drinking water to checking damaged buildings and controlling disease-carrying mosquitoes. In its World Cities Day feature, the International Atomic Energy Agency highlights seven applications that connect nuclear technology with urban health, safety and reliable services. The examples show how these tools can support communities facing water shortages, pollution, growing populations and infrastructure risks. The applications extend beyond electricity generation, using reactor heat, radiation and isotopic analysis to solve different problems. Some are already operating at city or industrial scale, including nuclear heating in China and mobile wastewater…