Shanghai is again blanketed in smog triggered by the pollutants from northern China this morning, forecasters said.
The air quality worsened this morning with its index peaking at 221 at 10am, meaning heavily polluted, local environmental monitoring center said.
The concentration of main pollutant PM2.5 particles hit about 170 micrograms per cubic meter at 10am, almost seven times the safety guideline set by the World Health Organization.
According to the Shanghai Meteorological Bureau, city's high humidity and weak winds make it difficult for the pollutants hard to be dispersed.
The smog is likely to linger until this afternoon and is expected to ease in the evening after the weak northwesterly winds transfer to northeasterly ones.
Tomorrow and Wednesday the air quality will return to the "good" tier because the rain will make its way back to Shanghai and wash away the pollutants. However, starting Thursday, since another series of cold airs will hit the city, the pollution may appear again along with the dryness and coldness.
