Seattle judges banned together and got rid of 15-years of cannabis convictions.
Possession of marijuana became legal in the state of Washington in 2012.
City Attorney Pete Homes asked the court to take the step “to right the injustices of a drug war that has primarily targeted people of colour.”
Officials estimate that more than 542 people could have their convictions dismissed by mid-November.
Per BBC
Mr Holmes said the city should “take a moment to recognise the significance” of the court’s ruling.
“We’ve come a long way, and I hope this action inspires other jurisdictions to follow suit,” he said.
Mayor Jenny Durkan also welcomed the ruling, which she said would offer residents a “clean slate.”
“For too many who call Seattle home, a misdemeanour marijuana conviction or charge has created barriers to opportunity – good jobs, housing, loans and education,” she said.
A total of 30 states in the US now allow the use of marijuana for medical purposes. In Washington state, it has been legal for medical use since 1998.