Sweeping smoking bans took effect last week in Canada's two most-populated provinces, Ontario and Quebec, amid protests by smokers that the prohibitions are unfair.

The Smoke-Free Ontario Act banned smoking "in all enclosed public places and workplaces, including restaurants, bars, schools, private clubs, sports arenas, entertainment venues, work vehicles and offices."

A smoking ban enacted last week in Kenya states that anyone smoking in a public place will be fined 50,000 Kenyan shillings ($700) or sentenced to 6 months in prison. Uganda and Tanzania have already banned smoking in public places.

And China, home to 350 million smokers, will ban smoking on public transport and in all indoor workplaces as part of plans for a tobacco-free 2008 Beijing Olympics.

Butting out in the United States: Thirty-one states ban smoking indoors at work places, and 12 prohibit smoking in public places, including restaurants, bars, clubs and some casinos. California, the first state to ban smoking inside public places, also leads the nation in outdoor restrictions. More than a dozen cities and towns along the California coast prohibit smoking on beaches, with varying degrees of enforcement.

What supporters of the bans say: Anti-smoking groups argue that secondhand smoke is a major public health problem; that smokers impose enormous costs on the rest of society; and that for all these reasons, taxes on cigarettes should be raised and restrictions be placed on the use of tobacco.

What critics say: Critics of smoking bans say the fight is over personal freedom and government intrusion on business. Smokers' rights groups contend that no scientific or medical data indicate that curbs on outdoor smoking are effective or necessary. Bar and restaurant owners worry their business will decline as more restrictions are placed on their clientele.

Germany, a heavy smoking country with high state revenues from tobacco taxes, was one of a handful of rich states in the World Health Organization to oppose a planned global anti-smoking treaty.

What Big Tobacco says: The tobacco industry also isn't enthusiastic about severe restrictions like those imposed in California. "Complete bans on outdoor smoking go too far," said Jennifer Golisch, a spokeswoman for Philip Morris USA, the world's largest cigarette maker by sales. "Smoking should be permitted outdoors except in very particular circumstances, such as outdoor areas primarily designed for children."