Since 2015, ITU's Study Group 20 on loT and its applications has developed various standards on smart cities and communities. Recommendation ITU-T L.1600 provides an overview of key performance indicators (KPIs) and indicators for a global framework of city indicators with reference to the UN Habitat's City Prosperity Index. Recommendation ITU-T L.1601 defines these KPIs. Recommendation ITU-T L.1602 focuses on the sustainability impacts of ICT for smart sustainable cities.