Conditions brought about by massive migration to cities generate new challenges for the studying of the commons, including urban agriculture, parks conservation, and the adequate provision of water and open spaces for recreation.  In addition, proposals under this track may explore the commons in relation to the following topics: energy flows and materials in urban ecosystems, water and urban waste management, public spaces, gentrification, "environmental racism", environmental justice, popular epidemiology, green belts, and urban zoning.