Officials of Suginami Ward, Tokyo, said Wednesday they will propose that a 5 yen tax be imposed on each petroleum-based plastic shopping bag used in the ward's supermarkets and grocery stores, with the aim of reducing garbage.

Ward officials said the special-purpose tax, to be proposed during the ward's regular assembly beginning Nov. 2, is expected to generate an estimated 400 million yen annually. The funds would be used for various activities, including the preservation of old trees.

Under the proposed bill, stores would charge an extra 5 yen for each plastic bag a customer uses. The amount will then be paid to the ward office, they said.

Ward officials said they hope to reduce the overall use of plastic bags, estimated to reach 169 million annually, by 60 percent.

If adopted, the ordinance would take effect after it is approved by the minister of public management, home affairs, posts and telecommunications. Officials said they hope to introduce the measure in the ward after a one-year notification period.

Similar independent tax systems mapped out by local governments include a tax on anglers on Lake Kawaguchi in Yamanashi Prefecture and Mie Prefecture's tax on industrial waste.