BEIJING — Declaring war on the “white pollution” choking its cities, farms, and waterways, China is banning free plastic shopping bags and calling for a return to the cloth bags of old — steps largely welcomed by merchants and shoppers yesterday. The ban takes effect June 1, just before Beijing hosts the Summer Olympic Games, ahead of which it has been demolishing run-down neighborhoods and working to clear smog.

The measure eliminates the flimsiest bags and forces stores to charge for others, making China the latest nation to target plastic bags in a bid to cut waste.

Internationally, legislation to discourage plastic bag use has been passed in parts of South Africa, Ireland, and Taiwan, where authorities either tax shoppers who use them or impose fees on companies that distribute them. Bangladesh already bans them, as do at least 30 remote Alaskan villages. In America, which has less than one-quarter of China’s 1.3 billion people, the Sierra Club estimates almost 100 billion plastic bags are thrown out each year.