BEIJING, Dec. 31 (Xinhua) -- Traffic in parts of northern China has been disrupted due to heavy smog and fog Saturday, the start of the three-day New Year holiday.

According to Beijing Traffic Management Bureau, dense fog has reduced visibility to around 50 meters on some expressways. Sections of seven expressways have been closed down as of 9 a.m.

Traffic in neighboring Hebei Province has been affected by heavy smog. Expressways in nine cities in the province were shut down.

The provincial capital Shijiazhuang has been implementing odd-even plate restrictions on vehicles for over a month.

A local resident said he was happy the restriction will be lifted on Jan. 1 and 2, but the closing of an expressway had ruined his holiday plan.

Beijing was put on orange alert, the second-highest level, Friday. The alert will continue through Saturday and Sunday.

Eight cities in Hebei activated red alerts Thursday night.