The Chicago City Council voted overwhelmingly today to decriminalize the posession of small amounts of marijuana, giving police the discretion to write tickets instead of arrest violators, the Chicago Tribune reports.

The proposal, put forth by Mayor Rahm Emanuel, passed, 43-3.

The new law, covering possession of 15 grams of marijuana or less, could take effect as soon as July. Fines would run between $250 and $500.

Reuters notes that Chicago joins such cities as Seattle, Pittsburgh and Philadelphia, as well as university towns like Champaign, Ill., and Madison, Wis., in adopting more lenient policies for pot possession.

To win support, Emanuel tweaked his original proposal to add the possibility that violators could be required to do community service or take part in drug awareness or educational programs.

The Tribune quotes Chicago Police Department Superintendent Garry McCarthy as saying that charges are dropped against the "vast majority" of about 20,000 people arrested each year for possession of small amounts of pot.

Each arrest, he says, take up to four hours of police time, the Tribune reports.