“When we had a sandstorm last week，I had to get up half an hour earlier so I wouldn't be late for school，”said Xing Wei，a Junior I boy at Yaohua Middle School in Tianjin. Xing usually gets up at about seven and needs 20 minutes to get to school. But on sandstorm days, he needs 40 minutes. When the sky is dark with sand, buses and cars all move much more slowly. Sometimes, people can't even see for 200 meters.