Peak-hour traffic in chaos and flights CANCELLED as a thick blanket of fog swallows Sydney

Sydney is covered in a heavy blanket of fog which has sparked flight cancellations and is expected to plunge peak-hour traffic into chaos.

Visibility in parts of the city was down to just 50 metres on Thursday morning, as the Harbour Bridge and the Sydney Opera House disappeared behind the think mist.

Western Sydney is the worst affected, with a ferry at Parramatta forced to turn back due to the dangerous conditions.

The Harbour Bridge (pictured) and the Sydney Opera House disappeared behind the think mist

Temperatures plummeted to just 11C in the city and as low as 8C in the west. 

Daily Mail Australia understands a number of domestic flights out of Sydney Airport have been cancelled or delayed due to poor visibility.  

Travellers have been told to contact their airlines for further information.

Drivers have been urged to turn on their fog lights and use caution on the roads. 

The foggy conditions come as temperatures plummeted to just 11C in the city and as low as 8C in the west

Several ferries across the city have been cancelled or delayed due to poor visibility 

The city (Darling harbour pictured) is expected to plunge into peak-hour chaos on Thursday morning

Some ferries between Manly and Circular Quay, Taronga Zoo, Mosman, Double Bay and Watsons Bay have also been cancelled or delayed.

‘Allow extra travel time as ferry services may be delayed or cancelled due to heavy fog this morning,’ Transport NSW said.

‘Expect delays and cancellations and check indicator boards as ferry stopping patterns may change at short notice.’

More to come.  

Visibility in parts of the city is down to just 50 metres. The Manly ferry is pictured on Thursday morning 

Daily Mail Australia understands a number of domestic flights out of Sydney Airport have been cancelled or delayed due to poor visibility