In April, Arizona became the first state in the country to ban plastic bag bans. Now, the state is being sued over it.

Tempe City Councilwoman Lauren Kuby is behind the lawsuit, though she’s acting as a private citizen. She calls the so-called “ban on bans” unconstitutional and said that plastic bags ordinances are “gateway legislation,” which can encourage citizens and local governments to think in new, greener ways.

“Plastic pollution has such impacts on the environment and the economy and public health,” she said. “It’s one of those rare cases when you’re working on a local level where you can have such impact with one piece of legislation.”

To have state officials who often think the federal government has too much power “stepping in and telling cities that they can’t regulate plastics, they can’t regulate Styrofoam is such an overreach,” she said, “that I felt as a private citizen, I had to stand up and act.”

Kuby’s lawsuit comes more than a year after Bisbee became the first city in Arizona to ban plastic bags. Kuby supported a similar ban for Tempe before the state law prohibiting them went into effect.