To learn how your city compares to other cities your size check out Smarter Cities , a project of the Natural Resources Defense Council (NRDC). The mission of Smarter Cities is to nudge cities towards friendly competition about sustainability. The website has a wealth of information about best practices and ideas cities are employing to become greener. You can even take a quiz to see how city smart you are about urban rehabilitation, sprawl, green space, green building, renewable energy, energy conservation, water, transportation, food, recycling and air.

Cities fall into three population categories, small cities with populations from 50,000 to 99,999 people (408 cities), medium cities with populations from 100,000 to 249,999 (178 cities) and large cities with populations of 250,000 and over (67 cities).

The rankings here are especially useful because they explain the criteria used and the method of scoring: air quality, energy production and conservation, environmental standards and participation, green building, green space, recycling, transportation, standard of living, and water quality and conservation.

Cities are rated for each criterion and the 15 top ranked cities for all categories are highlighted in each group. Seattle, Washington is the top large city. Madison, Wisconsin is the top medium city. Bellingham, Washington is the top small city.

In addition, there is ranking for each criterion. For example, in the small city category Bellingham has the cumulative top ranking and individual top ranking in air quality and green space. Mountain View, California, is ranked highest for transportation, energy production and conservation, and water quality. Petaluma, California is ranked top in standard of living. Beaverton, Oregon is rated highest for green building. Fayetteville, Arkansas is ranked top for environmental standards and participation. Mission Viejo, California is ranked highest for recycling.

You can add your city if it is not already included in the database.