China is about to try to kick a three billion-a-day plastic bag habit. But breaking the addiction, in a bid to save energy and protect the environment, will be easier said than done.

The world's most populous nation on Sunday will join a growing list of countries, from Ireland to Bangladesh, that are aiming to change shoppers' habits when a ban on the production of plastic bags under 0.025 millimetres thick comes into force. Ultra-thin bags are the principal target of the crackdown because they are typically used once and then discarded, adding to waste in a country that is increasingly conscious of the air and water pollution caused by its breakneck economic growth.

Shopkeepers will also be barred from handing out free plastic carrier bags except for fresh and cooked foods. Those breaking the law face fines and could have their goods confiscated.

China consumes 37 million barrels of what is now very expensive crude oil each year to churn out the three billion plastic bags that its 1.3 billion people use on average each day, according to official figures.

Ma Zhanfeng, secretary-general of the China Plastics Processing Industry Association, expects the ban to bite. "Domestic demand for plastic bags will drop drastically from 1.6 million tonnes a year to around 1.1 million tonnes," said Ma, who has nearly 20 years' experience in the industry.

Bag makers have already felt the pinch from the looming restrictions. Some have even been forced out of business. But Ning Rongju with Friends of Nature, a local non-governmental organisation, says all will depend on whether the new rules are enforced, especially in cities such as Beijing, where demand for bags in the capital's many markets is huge. "The execution and monitoring of the law will actually determine the future of plastic bags," she said.

Xiao Ling, the mother of a 6-year-old boy, said her family was already in the habit of using nylon shopping bags. But she, too, was sceptical. "Getting rid of all ultra-thin bags will take a long time," she said while out shopping at a Wal-Mart supermarket in Beijing.