Four Bay Area cities rank in top 10 greenest cities in America, here's why

Some of the greenest living cities in the U.S. call the Bay Area home, according to a recent WalletHub study.

The report ranked San Francisco as the fourth greenest city in the nation, with San Jose following closely at No. 5. Oakland trailed not too far behind, placing seventh and Fremont at No. 9.

Wallethub described green living as "engaging in cleaner, more sustainable habits in order to preserve the planet." The report compared the clean energy and green practices of America's 100 largest cities, including factors like recycling programs, greenhouse-gas emissions per capita and water quality.

The tap key components analyzed included the environment, transportation, energy sources and lifestyle/policy of cities.

WalletHub ranked San Diego as the greenest city in America, citing that "over 43% of the city's electricity comes from renewable sources." Washington D.C. ranked at No. 2, with Honolulu coming in third.

Here's a look at the top 20 greenest cities in America:

RANK	CITY
1	San Diego, Calif.
2	Washington D.C.
3	Honolulu, Hawaii
4	San Francisco, Calif.
5	San Jose, Calif.
6	Seattle, Wash.
7	Oakland, Calif.
8	Portland, Ore.
9	Fremont, Calif.
10	Irvine, Calif.
11	Minneapolis, Minn.
12	Denver, Colo.
13	Sacramento, Calif.
14	Buffalo, N.Y.
15	Madison, Wis.
16	Chula Vista, Calif.
17	Anaheim, Calif.
18	Los Angeles, Calif.
19	Long Beach, Calif.
20	St. Paul, Minn.