City's efforts to clean up pay off

For the past one-and-a-half years, Ji Xuexin has been carrying weight scales to work in Zhongwei in the Ningxia Hui autonomous region.

Along with 10 other colleagues, Ji checks if the dust from 1 square meter of road surface randomly collected at 60 points in the city exceeds 5 grams.

Ji, 33, is an inspector with a team of road sweepers in Zhongwei. The city, with a population slightly over 1 million, is at the edge of the Tengger Desert, one of China's four major contributors of sandstorms.