A South Korean research institute is blaming pollution from China for poisoning the air at a famous South Korean tourism spot, the Yonhap News Agency reported on Wednesday.

The South Korea National Institute of Environmental Research (NIER) found the average concentration of airborne particles including lead at Cheju Island, a South Korean tourist hotspot on the Yellow Sea, rose to 107 microns per cubic meter, 7 micrograms above the clean-air standard on Saturday and Tuesday.

The NIER said the pollutants were blown to South Korea by winds from China. A Chinese expert said the research institute's conclusion was made too hastily.

"It's difficult to assert that the heavy air pollution in China resulted in a decline in air quality on Cheju Island," Zhang Yuanxun, a professor of resources and environment at the Chinese Academy of Social Sciences, told the Global Times.

Zhang noted that it's not likely China-made pollutants could have made it to Korea because the lack of wind in North China from Saturday to Tuesday was one of the reasons the air quality index here soared.

China and other countries, including South Korea, have carried out cooperation for many years on trans-boundary pollution control, according to Zhang, adding that similar cooperation on combating air pollution would be carried out in the future.

China's central meteorological station lifted its smog alert at 10 am on Wednesday in the country's central and eastern areas, the Xinhua News Agency reported.

Heavy fog enveloped a large swathe of East and Central China on Saturday, causing highway closures and flight delays in several provinces.

Beijing was shrouded in dense smog for a second straight day on Saturday. The elderly, and children in the capital have been advised to stay indoors to reduce exposure to polluted air.