Less than a month into the program, which D.C. officials describe as an effort to reduce litter and generate funds to clean up the Anacostia River, the nickel bag fee is having a big impact. Managers at stores that sell food or beverages say the switchover has cut the use of plastic bags by half or more. One Safeway in Northwest reports a falloff of more than 6,000 bags a week, about half of its former volume.

DC’s tax on plastic bags seems to be working well (“This is like a behavioral economist’s dream”). The idea is something Mick Dumke’s been writing about for a while. Via Ezra Klein, who discusses it in the context of health care and the excise tax.