WASHINGTON (Reuters) - The District of Columbia stepped closer to decriminalizing marijuana on Wednesday when a city council panel approved a measure that would make smoking a joint in the U.S. capital a violation comparable to a parking ticket.

A fully budded marijuana plant ready for trimming is seen at the Botanacare marijuana store ahead of their grand opening on New Year's day in Northglenn, Colorado December 31, 2013. REUTERS/Rick Wilking

Approved unanimously by the city council’s public safety committee, the bill reduces penalties for possessing less than an ounce (28 grams) of marijuana to a fine as little as $25.

Eight times more blacks than non-blacks in Washington are arrested for pot possession, and committee Chairman Tommy Wells said the measure’s goal was fairness and reducing law enforcement costs.

“This is a social justice bill that addresses disproportionate impact,” said Wells, who is among nine candidates for mayor in the April 1 Democratic primary.

If the full council passes the measure, Washington would join 15 U.S. states and a handful of cities that have decriminalized marijuana use. Wells said the bill could become law before April.

The proposal eliminates criminal penalties for possession and the $25 fine is less than most city parking tickets. People smoking in public would be fined $100, and minors would also have a letter sent to their parents.

Passage is likely since nine of 13 council members and Mayor Vincent Gray support the measure. Possession of any amount of marijuana in Washington is currently a misdemeanor carrying up to six months in jail and a $1,000 fine.

A Washington Post poll released on Wednesday showed that 63 percent of city residents favored legalizing marijuana, up from almost half in 2010.

A group of District activists is also seeking to put an initiative on the November ballot that would legalize possession of small amounts of pot for personal use.

The Washington measure comes after two states, Colorado and Washington, have legalized marijuana. New York Governor Andrew Cuomo also came out this month in favor of allowing the limited use of medical marijuana.

Support for decriminalizing marijuana in the shadow of the U.S. Capitol was boosted by an American Civil Liberties Union report in June showing that blacks were far more likely to be arrested than non-blacks for possession.

In 2010 the capital had a higher pot arrest rate than any state, at 846 arrests per 100,000 people, the report said.

Spokesmen for the District’s three medical marijuana dispensaries said the price of an ounce of medical pot started at about $300 an ounce.

The Washington decriminalization law could face scrutiny from Congress, which has constitutional oversight over the capital.

But Erik Altieri, a spokesman for the National Organization for the Reform of Marijuana Laws, expected little resistance from Congress since lawmakers have not tried to pre-empt similar measures in other jurisdictions.

Also, Congress tends to be more concerned with spending and budget matters involving Washington, and the district could portray decriminalization as a way to cut costs, he said.

A spokesman for the House of Representatives’ Oversight Committee did not respond to a request for comment.