A view of an expressway toll station amid heave fog in Xi'an, Shaanxi Province. Heavy fog blanketed some parts of the northwestern province of Shaanxi on the morning of December 24. Visibility was reduced to less than 10 meters, forcing the closure of the Xi'an-Baoji expressway and causing great difficulty to passengers.

A passenger bus moves along a street amid heavy fog.

A farmer plods his tractor out of safety concern on a street.

Cyclists move forward on a street.

(China Daily December 25, 2006)