It also requires retailers to charge customers for thicker plastic bags not covered by the ban.

Environmentalists say plastic bags can take up to 1,000 years to disintegrate and pose threats to marine life, birds and other animals.

Here is a list of some of the countries that already restrict plastic shopping bags or plan to do so.

AFRICA -- Rwanda and Eritrea banned the bags outright, as has Somaliland, an autonomous region of Somalia. South Africa, Uganda and Kenya have minimum thickness rules, and Ethiopia, Ghana, Lesotho and Tanzania are considering similar measures.

AUSTRALIA -- Coles Bay in Tasmania became "Australia's First Plastic Bag-Free Town" in April 2003. Dozens of others followed suit. In January 2008, the environment minister called for supermarkets to phase out use of the bags nationwide by the end of the year.

BANGLADESH -- The first large country to ban bags in 2002. Bangladesh blamed millions of discarded bags for blocking drains and contributing to floods that submerged much of the country in 1988.

BHUTAN -- The isolated Himalayan country banned plastic shopping bags, street advertising and tobacco in 2007, as part of its policy to foster "Gross National Happiness".

CHINA -- The ban on ultra-thin bags that goes into force on June 1 will cut pollution and save valuable oil resources, the State Council, or cabinet, says. In May 2007 Hong Kong proposed a 50 cent "polluter pays" levy on plastic shopping bags.

ENGLAND -- In May 2007 the village of Modbury in south Devon became Europe's first plastic bag-free town, selling reuseable and biodegradable bags instead. London's 33 councils plan to ban ultra-thin bags from 2009 and tax others.

FRANCE -- In 2005, French lawmakers voted to ban non-biodegradable plastic bags by 2010. The French island of Corsica became the first to ban plastic bags in large stores in 1999.

INDIA -- The western state of Maharashtra banned the manufacture, sale and use of plastic bags in August 2005, after claims that they choked drains during monsoon rains. Other states banned ultra-thin bags to cut pollution and deaths of cattle, sacred to Hindus, which eat them.

IRELAND -- A plastic bag tax was passed in 2002. The tax created an initial 90 percent drop in bag use, according to the Environment Ministry, though usage gradually rebounded.

ITALY -- Outright ban to be introduced from 2010.

TAIWAN -- A partial ban in 2003 phased out free bags in department stores and supermarkets and disposable plastic plates, cups and cutlery from fast food outlets. Most stores charge people who don't bring their own T$1 ($0.03).

UNITED STATES -- San Francisco became the first and only US city to outlaw plastic grocery bags in April 2008. The ban is limited to large supermarkets.

The state of New Jersey is mulling phasing them out by 2010.

In January 2008 New York City mayor Michael Bloomberg signed a bill forcing large retailers to set up plastic bag recycling programmes and to make recycled bags available.