JUNE 13–GENEVA, Switzerland–The World Health Organization lifted SARS-related warnings against unnecessary travel to four regions of China, while Beijing remains under an advisory that helped cripple traffic at its biggest airport last month, officials said.

Travelers are no longer being told to avoid Hebei, Inner Mongolia, Shanxi and Tianjin in China, according to the United Nations health agency. Officials continue to investigate the spread of SARS in Beijing, China’s capital, said Iain Simpson, a spokesman for the organization.

“Beijing still has a high level of local transmission,” Simpson told Reuters . “We and local health authorities still have a large number of questions.”

China has reported more than three-fifths of the world’s 8,454 cases of severe acute respiratory syndrome, according to the World Health Organization. Beijing Capital International Airport Co., China’s biggest airport manager, said passenger traffic there plunged 87 percent in May because of SARS, and travel on domestic and international routes dropped more than 80 percent.

The only remaining advisories against travel affect Taiwan, which has reported 693 SARS cases and 81 deaths, and Beijing, the statement said. The epidemic has killed 792 people worldwide.

A team of World Health Organization experts led by David Heymann, executive director of the agency’s communicable disease program, is in China investigating the response to the epidemic, said Mike Ryan, agency coordinator of global alert and response. Heymann is impressed with infection control in China, Ryan said.

“He’s been getting big data downloads from the Chinese and was pleased with what he saw over the last few days,” Ryan said in an interview. “We’re comfortable enough now to remove the travel recommendations on those four provinces.”