Moderate to heavy pollution is set to hit Shanghai today and tomorrow.
This is due to sand and pollutants being carried into the city from the northern part of the country, according to the Shanghai Environmental Monitoring Center.
The peak of the pollution is expected to occur from tonight to noon on Saturday, with the average air quality index reaching 175, or moderately polluted, late tonight.
PM10, tiny particles in the air that are hazardous to health, will be the major pollutant.
A short spell of heavy pollution, with the AQI surpassing 200, is also expected. The situation should start to ease from Sunday.
A sandstorm swept over much of north China, including Beijing, yesterday, turning the sky yellow and obscuring visibility.
The pollutants were carried into the Yangtze River Delta region by a northwest wind.
Shanghai will see a slight rise in temperatures over the weekend as today marks lixia in the lunar calendar, a solar term referring to the beginning of summer.
However, it will still take a few weeks for Shanghai to enter summer meteorologically.
According to Shanghai Meteorological Bureau, today will be mostly cloudy with temperatures ranging between 18 and 23 degrees Celsius. Tomorrow will be sunny.
The highest temperature is forecast to climb to 25 degrees on Sunday, though showers can be expected in some parts of the city later in the day.
Lixia usually arrives during May 5 to 7 when the sun's elliptical longitude reaches 45 degrees, indicating the start of a new season that features rises in temperatures, frequent thunderstorms and the peak season for crops and fruit.
Only when the average temperature reaches 22 degrees for at least five days in a row, which usually happens in late May or early June, will the arrival of summer be officially announced.