What can cities, municipalities and communities do to significantly enhance environmental awareness among its citizens?

Cities worldwide face tremendous pressure on a number of environmental and ecological dimensions – air pollution, water scarcity, traffic congestion and more. One way for these cities to transition to a more sustainable future is through significant citizen participation. How can cities worldwide create effective awareness among its citizens, to make them adopt more sustainable practices, as well as to make them participate in community efforts to make the city green?