Marijuana decriminalization takes effect in the District of Columbia on Thursday, part of an easing of pot penalties in the U.S. capital that has drawn fire from Congress.
The District of Columbia joins 17 states that have reduced penalties for first-time violators to a fine and a civil, or minor, offense. Two states, Colorado and Washington, have legalized recreational use of marijuana.
Democratic Mayor Vincent Gray signed the decriminalization law in March. It took effect after a review by Congress, which under the U.S. Constitution has oversight over the District.
The law makes possession of up to an ounce (28 grams) of marijuana by people 18 or older a civil offense subject to a $25 fine and seizure of the drug and paraphernalia.
Possession had been a misdemeanor carrying up to six months in jail and a $1,000 fine. Consumption of marijuana in public is a misdemeanor.
The fine is less than most parking tickets and lower than in any state, according to the Marijuana Policy Project, an advocacy group.
The District of Columbia law also is unique in that the smell of marijuana alone is not sufficient grounds for a search by police, said Robert Capecchi, the project's deputy director of state policies.
Supporters of the decriminalization law portrayed it as a civil rights issue since blacks in Washington were more likely to be arrested for possession than people of other races.
The law has drawn opposition from Congress. A spending bill in the Republican-controlled House of Representatives includes an amendment barring the city from spending money to legalize or reduce penalties for marijuana.
The measure would take effect if it went through Congress intact and if President Barack Obama signed it. He said on Monday that he opposed the House bill and that the marijuana amendment undermined the principle of states' rights.
Backers of legalized marijuana in Washington are trying to put the question on the Nov. 4 ballot. The City Council also is debating a measure that would allow marijuana sales in the District of Columbia.