The simple plastic bag has come to symbolize the world’s growing problem with plastic waste. Yet globally, there are seven definitions of what is considered a plastic bag—and that complicates efforts to reduce their proliferation. 

Banning bags, along with other plastic packaging, is the most commonly used remedy to rein in plastic waste. So far, 115 nations have taken that approach, but in different ways. In France, bags less than 50 microns thick are banned. In Tunisia, bags are banned if they are less than 40 microns thick.

Those kinds of differences create loopholes that enable illegal bags to find their way to street vendors and market stalls. Kenya, which passed the world’s toughest bag ban in 2017, has had