Shanghai's air will be heavily polluted this morning before it eases in the afternoon, forecasters said yesterday.

But the good news is that it should be mainly sunny and warm until the beginning of next week, they said, although a cold front from the north would bring gales and low temperatures after that.

Photo taken this morning shows Shanghai shrouded in heavy fog and smog. Low visibility has disrupted air, water and road transportation.

Today's choking weather is mainly blamed on PM2.5 as the top pollutant, the Shanghai Environmental Monitoring Center said.

Current weather conditions — a cold high pressure and lack of wind — make it difficult to disperse pollutants, the center said.

The city's air was moderately polluted yesterday.

Today should be sunny and cloudy with temperatures ranging from 9 degrees Celsius to 17 degrees.

Tomorrow will be cloudy to overcast, with similar temperatures.

On Saturday, the sun will reappear although temperatures may drop to 14 degrees, then rebound to 17 degrees on Sunday, another sunny day.

Monday's cold front will reduce temperatures to between 8 and 12 degrees.