LOS ANGELES — On a recent drizzly day, Esha Moya found herself standing outside a grocery store in South Los Angeles, her half-dozen paper bags falling apart in the rain, wishing she had a few small items that had been free and plentiful her entire life but are now banned in this city: plastic shopping bags.

“I hate this,” said Ms. Moya, a telemarketer and a mother of two. She has begun stockpiling plastic bags at home because paper bags “are always breaking,” she said. “It’s stupid, and it makes it really hard for us.”

A companion to shoppers for a half-century, the plastic bag is now under siege in California, where a growing number of policy makers have come to regard it as a symbol of environmental wastefulness.

Since 2007, plastic shopping bags have been banned in nearly 100 municipalities in the state, including Los Angeles, which at the start of this year became the largest city in the country to enforce such a ban. Paper bags, which are biodegradable and easier to recycle, are often available for a small fee.