• Sustainable cities
• Smart cities
• Smart sustainable cities
• Smart eco-cities
• Artificial Intelligence of Things (AIoT)
• City Brain
• Urban Digital Twin (UDT) 
• Internet of City Things (IoCT)
• Urban Metabolism and Circularity
• Platform urbanism 
• Environmental sustainability
• Environmental planning
• Environmental governance
• Renewable energy and energy efficiency
• Sustainable and smart transportation and mobility
• Sustainable and smart waste  management 
• Climate change adaption and mitigation
• Sustainability transitions