Emergency WA has issued a smoke alert for the metropolitan area and the Hills as a shroud of smog blankets Perth on Wednesday afternoon.

Eerie pictures show the city skyline hidden behind a veil of smoke, as well as a billowing cloud above the Perth Hills.

The smoke is coming from a prescribed burn south-east of Mundaring, with safety warnings being issued for drivers heading home.

“Smoke may affect roads in the area and motorists are asked to drive to conditions,” the alert said.

Alerts have also been issued in the Shire of Bindoon to the north and City of Mandurah to the south.

WHAT TO DO

• Shut doors and windows and turn off air-conditioners.
• If driving through the area, turn on headlights and drive slowly. If you cannot see clearly, pull over to the left, keep your headlights and hazard lights on, and wait until the smoke clears.
• People with asthma and pre-existing respiratory or cardiovascular illnesses should follow their pre-prepared treatment plan.
• If affected by smoke contact your doctor or call 1800MEDICARE (1800 633 422).

The smoke is expected to clear on Thursday morning.