Many areas in the central province of Nghe An were covered in thick fog on Friday morning, including Vinh City where some flights faced delays.
At 9 am, many vehicles travelling in Vinh City had to turn their headlights on due to low visibility.
Le Loi Ward also got lost in the fog.
Some districts of Nghi Loc and Dien Chau still saw thick fog at 10 am.
National Road 1A from Nghi Loc to Dien Chau had 3-4 metres of visibility at noon.
Many drivers had to stop on the roadside due to low visibility. A driver, Nguyn Van Tu, said he faced difficulties driving his car due to the dense fog and could only drive at 30-40 kilometres per hour.
Authorities at the Vinh International Airport said that several flights had to be delayed including one from HCM City to Vinh and one from Hanoi to Vinh which were nearly an hour late.
