Major bushfire burn-offs in Sydney are causing heavy air pollution in parts of the city.
The controlled burn-offs are aimed at preventing out-of-control bush fires, but it's had the unfortunate side effect of choking Sydney's skyline in a smoky haze.
People with heart and lung conditions have been warned to stay indoors this weekend after air quality levels deteriorated to poor and hazardous.
However, there are long term benefits for the bushfire-prone state.
"While introducing fire is not inherently safe, it's a lot safer than if we wait until a fire is introduced in summer," says Rural Fire Service Deputy Commissioner Rob Rogers.
One such dangerous fires was in the Blue Mountains three years ago. It burnt out 65,000 hectares of land and destroyed more than 200 homes.
The controlled burn-offs can protect a fire prone area for up to seven years and the rural fire service has as many as 70 planned for this weekend across New South Wales.
The dry weather means conditions are perfect.
But there is some short term pain for the long term gain. In parts of Sydney air quality was officially rated as poor and hazardous.
The elderly, people with heart conditions and asthmatics are more vulnerable, so they are encouraged to stay in-doors while the smoke is at its thickest.
"A number of people have experienced complications as a result of the burns," says Anthony Flynn of Asthma Australia.
Rain and wind is expected to help clear the smoke, but that's not forecast for another week.
In the meantime, the official advice is to limit time outdoors.