According to different regions and ecological conditions, the sand hazard along the railway was divided into four types and nine grades.
因不同地带生态条件不同，引起铁路沙害可划分为四类九级。
2
The main ecological environment problems in the west China are a little rain and arid, serious hazard of wind sand, topography in pieces, vast hilly gully area and intense soil and water erosion.