AIR quality is expected to be good over the weekend, the Shanghai Environmental Monitoring Center said yesterday.
But the air quality index hit 180 at 8am yesterday. Heavy pollution is over 200.
The center said air quality last month was significantly better than the same month last year.
The number of days with good or excellent air quality rose to 26 from 17, with an average concentration of PM2.5 down 36 percent. In December, only 19 days had good air.