Heavy fog blanketed the northeastern province of Liaoning overnight, delaying flights on Apr. 8.

In Shenyang, capital of Liaoning Province, more than 20 flights that had been delayed started to take-off at around 10 a.m. on Apr. 8, according to the Taoxian International Airport.

The fog, which reduced visibility to 50 meters in the morning on Apr. 8, had virtually closed the airport, with no departures or arrivals before 9:40 a.m., said officials with the airport.

Xu Yang, a resident of Shenyang, described the fog as the most dense she had seen in more than two decades.

"When I got up this morning and looked out the window, I could barely see in the buildings opposite ours less than 100 meters away," said Xu.

Shenyang weather observatory said the fog was expected to disperse around noon on Apr. 8.