The toxic haze that has descended on Melbourne, where the year's first Grand Slam is due to begin next week, has drifted down from out-of-control blazes that have endured for months in eastern and southern Australia.
The bushfires, unprecedented in their duration and intensity, have claimed 28 lives while raising awareness about the type of disasters that scientists say the world will face due to global warming.
In Melbourne, a picturesque bayside city famed as one of the most liveable in the world, the bushfire smoke raised pollution levels to "hazardous" at the start of the week.
Australian Open organisers pushed ahead with qualifying rounds on Tuesday.
But dramatic scenes of players dropping to their knees and choking, and one retiring due to the smoke, led to complaints about them being forced to stay out on court.
With the air still tasting and smelling of smoke on Wednesday morning, organisers suspended qualifying rounds until 1:00 pm (0200 GMT).
Play then resumed under better but still hazy conditions.
Cool change hopes
A cool change, bringing thunderstorms and heavy rain, was due to sweep across southeast Australia from Wednesday afternoon and was expected to help clear the air in Melbourne.
There were also hopes that the forecast rain would help contain or even extinguish some of the dozens of fires still raging out of control and threatening to devastate many more rural towns.
The fires have already destroyed more than 2,000 homes and burnt 10 million hectares (100,000 square kilometres) of land -- an area larger than South Korea or Portugal.
The official death toll rose to 28 on Wednesday when authorities said they had confirmed a firefighter who died in late November in a traffic incident had at the time been trying to contain a blaze.
The fires have dominated headlines around the world and led to an international outpouring of aid for victims, as well as animals that have been injured in the blazes.
About one billion animals may have died in the fires and driven many species closer to extinction, according to environmental groups.
Australia's koala population has taken an "extraordinary hit" and could be listed as endangered for the first time, Environment Minister Sussan Ley has said.
In Melbourne, the smoke has raised the prospect of interruptions and delays for the two-week Australian Open, which is due to begin on Monday.
Slovenian Dalila Jakupovic was forced to retire while leading in her qualifying match on Tuesday because of the smoke.
"I was really scared that I would collapse," she said.
Former Australian Open semi-finalist Eugenie Bouchard also had problems on Tuesday and needed a medical time-out after complaining of a sore chest.
"Like the heat rule, there should be an air quality rule," the Canadian told reporters.
Other players, including world number five Elina Svitolina, hit out at organisers for allowing qualifying to go ahead on Tuesday.
"Why do we need to wait for something bad to happen to do an action," she tweeted.
Climate change debate
Meanwhile, a debate about the attitudes of Australia's political and media establishment to climate change continued on Wednesday with a rare intervention from one of Rupert Murdoch's sons.
James Murdoch hit out at his father's media empire, which includes the News Corp group that dominates Australia's press landscape as well as Fox News in the US, for climate change "denial".
James his wife Kathryn released a statement via the Daily Beast voicing frustration at the coverage by News Corp and Fox about climate change.
"They are particularly disappointed with the ongoing denial among the news outlets in Australia given obvious evidence to the contrary," the statement said.
News Corp publishes eight of the top 10 newspapers in Australia and operates the 24-hour Sky News satellite channel.
The conservative government led by Prime Minister Scott Morrison has also been heavily criticised by environmentalists and others for failing to do more to cut greenhouse gas emissions that are blamed for global warming.
Morrison has insisted his government is doing enough, and that he must protect jobs in the lucrative coal export industry.