Sydney smog: 'Hazardous level' air quality chokes residents - in pictures

'Poor to hazardous' levels of air quality as firefighters implement bush fire reduction burns

A jogger runs along Sydney Harbour as thick smoke blankets the greater Sydney Basin in Sydney.

A jogger runs along Sydney Harbour as thick smoke blankets the greater Sydney Basin in Sydney, Australia, 24 May 2019. Sydney residents have been experiencing 'poor' to 'hazardous' levels of air quality for the fifth day as bush fire reduction burns continue. All photos by Dean Lewins / EPA

A commuter ferry moves through the thick smoke blanketing Sydney Harbour.

A commuter ferry moves through the thick smoke blanketing Sydney Harbour in Sydney, Australia.

Thick smoke blankets Sydney Harbour and the greater Sydney Basin in Sydney, Australia. Sydney residents have been experiencing 'poor' to 'hazardous' levels of air quality for a fifth day as bush fire reduction burns continue.

The air quality in Sydney has dropped to "hazardous" levels through smoke and fog as Australia prepares to prevent catastrophic bush fires during its summer months.

Australian authorities urged older people, children, and anyone with heart or lung disease to avoid exercising outdoors and stay inside as much as possible, the Australian Associated Press reported.

Weather experts said the smog is lingering over Australia's biggest city due to a lack of wind.

The haze is being caused by rural fire brigades in New South Wales deliberately setting sections of the countryside on fire to halt the spread of out of control bushfires.

Australia experiences hundreds of wildfires each year with some of them raging into deadly infernos that threaten towns and kills scores of wildlife.

The deliberate fires have been halted to allow the lingering smoke to pass.