Nationwide, a broad range of environmental issues such as air and water pollution, threats to public lands, endangered species, environmental justice, longwall coal mining, mountaintop removal, community sustainability, public transportation, fracking, and climate change have motivated grassroots involvement. The movement has mobilized a variety of constituents, including retirees, students and other young people, religious groups, residents of affected areas, labor unionists, and long-time progressive activists. In Pittsburgh, the movement includes established organizations such as the Group against Smog and Pollution (GASP), Clean Water Action, PennEnvironment, and the Sierra Club, as well as newer environmental justice, climate action, and anti-fracking groups. Grassroots activists have employed a variety of tactics, from conventional lobbying and electoral politics to demonstrations and direct actions. They have organized numerous campaigns and participated in many alliances. The movement has frequently succeeded in engaging a large number of people, though many potential supporters have not become involved, and it is difficult to maintain organizations and collective action for an extended period of time. The movement has won some important battles, but continually struggles to make real progress in protecting the environment.