This document provides use cases on the practices of global cities and communities, including policies, supporting techniques and tools, and management approaches that drive towards achieving lower greenhouse gas (GHG) emissions for cities and communities as a key step towards net zero carbon cities in response to climate change and global carbon neutrality. This document takes into account varying contexts including climate conditions, scale, available resources or economic structures in these practices. This document is in line with the sustainability purposes and issues provided in ISO 37101 that are relevant to GHG emissions.