(CNN) Smoke from Australia's bushfires blanketed Sydney on Tuesday, creating unhealthy air quality conditions for locals -- which measured 11 times the "hazardous" level in some parts of the city.

New South Wales government's director of environmental health called the haze "unprecedented," Reuters reported.

"This smoky period we've been experiencing for the past month or so, it is unprecedented, so these conditions are a risk to people's health," Richard Broome said, according to Reuters.

Many locals are experiencing sore eyes, nose and throat irritations, he added, but those with pre-existing conditions, as well as young children and the elderly, "were at particular risk," Broome added.

Thick smoke shrouds the Opera House in Sydney on Tuesday.

Bushfire smoke smothered Sydney on Tuesday, setting off fire alarms, suspending ferry services and triggering health warnings over choking air pollution.

Famous landmarks such as the Sydney Opera House and the Harbour Bridge disappeared behind the thick haze, which has been caused by ongoing bushfires on the city's outskirts.

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