Dusts which polluted Beijing's air Friday backflowed Saturday from Beijing's east and south and continued to contaminate the capital's air on Sunday, according to an environmental expert.

Dusts which polluted Beijing's air Friday backflowed Saturday from Beijing's east and south and continued to contaminate the capital's air on Sunday.

Beijing's sky appeared yellowish for several consecutive days, and its air quality was below normal standard.

The dusts were blown from Mongolia and northwest China's Gansu Province, Ningxia Hui Autonomous Region and Inner Mongolia Autonomous Region, and began to affect Bejing on Friday, according to a report from Beijing's air quality monitoring stations.

The sands heading towards Beijing's southeast were however blown back to Beijing on Saturday, thus making the air pollution severe, said the expert.

But the dusts are expected to be dispersed late Sunday night, said the expert.