America's second greenest city, San Francisco, is apparently no longer content with being number two.

Earlier this week, the city's Board of Supervisors voted unanimously on an ordinance banning the sale and distribution of plastic water bottles 21 ounces or less on city property. If passed, the ban is expected to take effect for all indoor events held in city buildings or on land leased by the city starting this fall, and all events by 2016.

This is following the more extensive ban enacted by Concord, Mass. in 2013, which banned plastic water bottle sales anywhere in the town, including gas stations and grocery stores.

The goal, the SF Examiner reports, is to have "zero waste" going into the city's landfills by 2020. According to a 2006 fact sheet produced by the Pacific Institute, more than 17 million barrels of oil are used to produce plastic water bottles annually, and more than 2.5 million tons of carbon dioxide are produced as a byproduct of the bottling process.

The San Francisco ordinance still needs to undergo a second round of voting before reaching mayor Ed Lee.

In related news: mason jar sales in SF are expected to shoot through the sustainable farming rooftop.

H/T Mother Nature Network + Picthx Roger H. Goun