A Chinese scientist has called for intensified international cooperation to address sandstorms that have frequently left much of northern China shrouded in suffocating orange haze this year.

Northern China has been hit by 21 sandstorms, with one in mid-to late March the strongest in a decade, said Li Jianjun, chief scientist with the China National Environmental Monitoring Center.

"Such frequent, severe and wide-ranging sandstorms have rarely been seen in China in recent years," Li told a news conference on Wednesday.

He said sand from Mongolia was a major contributor to the sandstorms, which caused air pollution levels to spike in many Chinese cities.

Data from China"s National Meteorological Center shows that higher temperatures than normal in Mongolia and the western part of China"s Inner Mongolia autonomous region made them major contributors to sandstorms, he said.