SHANGHAI - A minor air pollution lingers over Shanghai and several other big cities in East China since Saturday.

Shanghai Environmental Monitoring Center (SEMC) released that the atmospheric PM10 index, or the inhalable particles in monitored air, reached 161 on Monday and 127 on Sunday, indicating minor pollution in air. A PM10 index between 151 and 200 is considered "minor" pollution.

Other cities in East China, such as Ningbo and Suzhou, have also experienced air pollution in recent days. Shaoxing in central Zhejiang province was the worst of all these cities, reaching 182 on the PM10 index, according to the China National Environmental Monitoring Center (CNEMC).

"Statistics from the CNEMC show similar pollution in the northern Jiangsu province and Shandong," said Duan Yusen, Shanghai center's chief meteorologist.

"In the absence of winds, pollutants in the air left by exhausts from vehicles do not get swept away easily, thereby causing air pollution," said Duan.

"The sky in Shanghai looked mostly gray and yellow these three days. Visibility in some places was limited to 1 to 3 kilometers on Monday morning. Some parts in southern and eastern Shanghai reached a visibility of no more than 100 meters," said Man Liping, chief service officer of Shanghai meteorological bureau.

"Residents said they smelled an odor in the air when they were out last night," said Man.

Strolling the roads in northern Shanghai on Sunday night, Yang Ge sensed an unusual smell.

"I could not tell what it was. The air was really humid. Parts of the road swept by automobile headlights looked really dusty. I had a sore throat last night," said Yang.

Man said a weak cold air would permeate the atmosphere in the following days, making foggy weather less likely in Shanghai.

"As the sun unveils and temperature goes up, visibility in northern Shanghai will reach around 3 km, and will also hugely improve in the southern parts of the city," she said.

Heavy smog in Beijing late in October caused the closure of six highways and delays or cancellations of more than 200 flights to or from the city.

Li Xinzhu contributed to this story.