Smoggy conditions continued in Shanghai this morning with the air quality index hitting the worst of a six-level scale, or the "severely polluted" level.

A woman wearing a mask walks past the Bund promenade today in Shanghai as smoggy conditions continue with the air quality remain "severely polluted".

The air quality index stayed above 200 after 1pm yesterday and had soared to 312 by 9am today, the sixth grade and also the highest level of air pollution.

The index rose to 315 at 10am, indicating a worsening condition.

By 10am, the density of PM2.5 particles peaked at 275.5 micrograms per cubic meter — more than three times the nation’s limit of 75.

Weather authority had issued a warning that children, the elderly and those suffering heart problems or respiratory illnesses should stay indoors while others were advised to cut down on outdoor activities.

The city's education watchdog had ordered all outdoor activities for students this morning to be cancelled for safety concerns.

Such smoggy conditions are expected to continue tomorrow as weather conditions make it unlikely that the pollutant particles can be dispersed.

However, the arrival of a cold front on Wednesday may mean an improvement in air quality.

“The stable air condition and the dominance of high pressure resulted in the air pollutants’ accumulation,” Wu Rui, a chief service officer at the Shanghai Meteorological Bureau, said yesterday.

The midweek cold front is likely to bring overcast skies to the city, but there should be little wind and rain.