he World Health Organisation (WHO) offered reassurances today that the radiation risk from Japan's nuclear crisis remains highly localised, with no sign it threatens anywhere else in Asia.
"To date, we don't have any information of a significant spread of radioactive material beyond the evacuation zone," said Michael O'Leary, head of WHO in China.
"At present, we still understand it's very confined. That's why there's an evacuation zone around the nuclear reactor itself."
Workers are fighting to cool the overheating reactors at the Fukushima nuclear plant in north-east Japan critically damaged by last week's earthquake and tsunami. The zone within 12 miles of the plant has been evacuated, while people within 20 miles were told to stay indoors.
Health experts say there is little risk beyond that, including in the capital of Tokyo, 140 miles away.
Still, China and other neighbouring countries increased monitoring of radiation levels, and fears of radioactive contamination have prompted panic-buying across China of iodised salt.
Shoppers in Beijing, Shanghai and other parts of China have stripped supermarket shelves empty of table salt in recent days in the false belief that it either wards off radiation injuries or that the nation's supply would be contaminated by radioactive fallout.
Experts have said the first rumour is not true and the second is unlikely: any catastrophe at the Japanese nuclear plant would most likely affect the immediate area, and wind patterns usually blow away from China at this time of year.
The rumours are part of a swirl of misinformation regarding Japan's nuclear emergency.
China Central Television reported today that China's salt makers have 2 million tons of salt in reserves and have stepped up production as the government seeks to control rampant sales.
"The panic buying at such a large scale tests our co-ordination and distribution abilities, but we have confidence we can resume the normal supply to the market within two weeks," Dong Yongsheng, deputy general manager of China National Salt Industry Company, told CCTV.
Beijing started a seven-day inspection on table salt prices. Those found to have illegally hiked prices will be punished, the city government said.
The National Marine Environmental Forecasting Centre reported last night that air and seawater levels in China are not under immediate threat. Ocean and wind currents are moving east, so any contaminants would be pushed into the Pacific Ocean, the forecasting centre said in a statement. China lies to the west of Japan.