"It is strictly forbidden to inject water or any other chemicals into pigs or pig meat products, and packing houses should properly store unsold meat," according to a draft regulation on the slaughter of pigs issued by the Legislative Affairs Office of the State Council, or the Chinese cabinet.

The draft regulation imposes stricter meat quality checkups and tougher standards for slaughterhouses.

"The location of slaughterhouses should not perturb the daily life of local people or damage the environment," it said, adding local departments should assess the impact of building a slaughterhouse on the local environment.

Butchers hired by slaughterhouses should have a health certificate and master special techniques, according to the regulation.

A standard slaughterhouse should have refrigeration equipment, quality assurance processes, satisfactory delivery and sterilization procedures, pollutant disposal and epidemic prevention, it said.

Some profiteering farmers inject chemicals into pigs or into pig feed to make their meat products more "attractive" in the country's livestock market.

Last November, Shanghai police arrested three people who had put three to four grams of the banned drug, clenbuterol, into each ton of pig feed to increase the lean meat.

In a single day, more than 300 people in the city developed symptoms of dizziness, fatigue, palpitations and tremors after eating the meat, and had to be hospitalized. Fortunately no deaths were reported.

Clenbuterol, or "shouroujing" in Chinese, can prevent pigs from accumulating fat, but is poisonous to humans and can be fatal.

China has banned the use of the chemical as an additive in pig feed.