On March 28, San Francisco became the first U.S. city to prohibit non-biodegradable plastic bags in supermarkets and drug stores. The ban, which will come into full effect later this year, adds an important voice to the growing global movement toward cutting down plastic bag usage worldwide.

Between 500 billion and 1 trillion plastic bags are consumed annually, including 100 billion in the U.S. alone, according to The Wall Street Journal. Each bag can take up to 1,000 years to break down, causing serious environmental impacts in the meantime. In addition, plastic bags kill an estimated 100,000 marine animals every year and contribute to devastating floods in urban areas by clogging drainage systems.

They can also affect tourism in sensitive environments. Zanzibar, an island off the coast of Tanzania popular for pristine coral reefs and beaches, cited littered bags’ harmful effects on the island’s marine life and tourism industry as reasons for its 2006 ban on the import and production of plastic bags.

Countries that have already taken action to limit the use of plastic bags include Australia, Bangladesh, Hong Kong, India, Ireland, Italy, Rwanda, South Africa, Scotland, and Taiwan. Other nations-such as China, France, Kenya, Pakistan, and the U.K.-are currently considering legislation to reduce plastic bag consumption.

Ireland’s PlasTax is one of the most effective programs. By charging about $0.20 per bag in combination with raising public awareness about related environmental issues, public consumption has dropped an estimated 95 per cent.

San Francisco’s Department of the Environment said that the city goes through 181 million plastic grocery bags per year. The new ban will save 450,000 gallons of oil a year (the amount currently required for the production of the bags) and reduce the debris sent to landfills by 1,400 tons annually.