Managing stormwater in cities using blue-green infrastructure (BGI) is becoming popular. BGI helps with water issues and makes cities better. Six pilot projects in Beijing and Copenhagen were studied. Beijing's projects need more BGI solutions for better results. Copenhagen's projects focus on making areas nicer but could do more with stormwater. Pilot projects are important for testing and improving new ideas for sustainable cities. Lessons learned include prioritizing water techniques, handling all rain events, and combining stormwater management with urban improvements. It's crucial to integrate stormwater management and landscape design for successful solutions.