CITY-WELLNESS proposed the development of a globally scalable, AI-powered Software-as-a-Service (SaaS) platform to support urban decision-makers in implementing zero-pollution strategies. Building upon Horizon 2020 NetZeroCities and EO4EU technologies, the platform integrates environmental monitoring, health risk assessment, and socio-economic indicators into a City Digital Twin (CDT) and a City-Wellness Index (CIWI).