According to the latest project report of the administration, the northern parts of the country suffered a total of 32 sandstorms during last year -- 56 percent of which were whipped up in southern parts of Mongolia.

The remaining 44 percent came mostly from the Inner Mongolia Autonomous Region.

The sources of the sandstorms which hit Beijing are similar to those in other parts of North China and Northeast China. Last year, the city bore the brunt of such storms 18 times.

Sandstorm disasters this year are expected to be as severe as last year in Beijing, predicted experts with the administration.

Satellite pictures have shown that 30 percent of land in Mongolia, which has a 4,212-kilometre border connected with China, is desertified. This is mainly located in southeastern parts of the country.

The desert in Mongolia, together with that in eastern parts of Kazakhstan, form one of the two major sources of the country's sandstorms.

Nearly one-third of western regions of the country -- especially the eastern parts of the Inner Mongolia Autonomous Region, southern and northern parts of the Xinjiang Uygur Autonomous Region -- are also suffering serious desertification, making them another sandstorm source.

Quan Hao, an expert with the administration in charge of the country's sandstorm research project which began in 1996, noted many sandstorms in these areas are not as damaging as those which rock cities in North China like Beijing and Tianjin.

Ecology along the route of the storms determines their severity in North and Northeast China, said Quan.

To cope with sandstorm disasters, scientists in charge of the project have called for a strong implementation of the central government's policy of returning land to pasture in the country's western regions the following years. They also call for the planting of trees to create an anti-storm forest barrier.

Scientists also urged the central government to strengthen environmental co-operation with Mongolia to develop a long-term anti-sandstorm strategy implemented by both countries.

Scientists have also suggested building an ecological wall around Beijing by planting more trees ahead of the 2008 Olympic Games.

Luo Yi, vice-director of the Science and Technology Department with the administration emphasized that anti-sandstorm goals cannot be achieved in the near-term but need the combined efforts of governments and communities over generations.

Sandstorms in China, which occur mainly between November and May, can travel from Mongolia or western regions to coastal cities in North China within a day.