A local smoking-control law came into effect Wednesday in Guangzhou, the capital of south China's Guangdong Province.

The law covers all of Guangzhou City. There, smoking in most public places, like offices, conference rooms, halls and elevators, is strictly prohibited.

Places of business larger than 150 square meters or having more than 75 seats may designate an area for smokers.

Those who break the law will be fined 50 yuan (about 7.35 U.S. dollars) and businesses not meeting their obligations will be fined up to 30,000 yuan.

However, some doubt the law is enforceable.

"Who is the enforcement agency and how do they collect evidence of smoking?" said a pedestrian on a street.

"A quick smoke can take less than one minute. How can an enforcement agency come in such little time?" a different pedestrian asked a Xinhua reporter.

Hu Angang, an economics professor at Tsinghua University, said weak smoking-control in China means measurable goals should be included in the twelfth national development plan.

"Putting goals into the national plan shows great political will from state leaders. So the whole of society, especially local governments, will implement it without hesitation. The plan is a binding document for the government," said Hu.

Shanghai began implementing a regulation to ban smoking in 12 types of public places March 1 in an effort to have a smoke-free World Expo.

Shanghai declined a 200-million-yuan sponsorship deal for the 2010 World Expo from a tobacco company in July 2009.

One of the world's largest tobacco producing and consuming nations, China manufactures about 100 billion packets of cigarettes each year.

It has a smoking population of 350 million, about one third of the world's total smoking population.