Single-use plastic bag bans have successfully reduced plastic bag use and associated litter and pollution, a new study has found.

Bans in five US states and cities with a combined population of around 12 million people have cut single-use plastic bag consumption by about 6 billion bags per year, according to the research.

Adopting a ban that’s similar to the policies in these places could eliminate roughly 300 single-use plastic bags per person per year, according to the report.