SYDNEY • Less than a fortnight before the start of the Australian Open, Melbourne lies under a thickening blanket of bush-fire haze, and air quality has been downgraded to "very poor" and "hazardous", which constitutes a serious health threat.

There is a chance the tournament will be delayed, although conditions are expected to ease before its Jan 20 start.

Smoke drifting across from Tasmania has mixed with continued pollution from fires in rural Victoria, and the air quality index broke through the 200 barrier in Melbourne yesterday evening, placing the city in fourth place behind known pollution black spots like Delhi and Lahore.

Seven-time Australian Open champion and favourite Novak Djokovic - who suffered respiratory problems early in his career - said at the weekend that air pollution at Melbourne Park, where the Slam is held, would have to be closely monitored.

The world No. 2 also did not rule out discussing a delay to the tournament if players' health was going to be compromised.

Yesterday, those concerns were given substance in statements from emergency services and the tournament organiser.

"We know it's a threat to life for some people," the state's chief health officer, Dr Brett Sutton, said.

Victoria's Environmental Protection Agency chief environmental scientist, Dr Andrea Hinwood, added: "We're not expecting (the air classification) to change until Wednesday...

"Drenching rain would be terrific because it would knock it out. But the current amount is insufficient and there's too much smoke."

Craig Tiley, the chief executive officer of Tennis Australia, remains optimistic the Slam will go ahead, but the organisers will continue to keep tabs on the air quality.

He said: "We have committed substantial extra resources to analysis, monitoring and logistics to ensure the health and safety of all players, staff and fans...

"We have access to real-time monitoring of air quality at all of our venues, and are working closely with medical personnel and local experts onsite to ensure we have the best possible information available to make any decisions regarding whether play should be halted at any point.

"The health of players, fans and staff is a priority at all times and we will continue to make these decisions with that in mind."

But Dr Sutton has warned pregnant women, asthmatics, diabetics and people with heart and lung diseases, as well as children under 14 and adults over 65, to take precaution by wearing P2 or N25 masks.

And with at least 24 people killed and hundreds of homes lost in the fires, tennis has become an afterthought instead of maintaining its usual status as a centrepiece of the Australian summer.

World No. 115 Denis Kudla, who is playing in Bendigo after the Challenger event was moved from Canberra last week, said of the potential conditions: "You could play, but who knows what damage we're actually causing to ourselves?

"Nothing has ever been close to postponing or cancelling a Slam, so this is going to be a tough decision, naturally.

"But if the smoke gets worse, I couldn't imagine potentially playing a four, five-hour match and not coughing like crazy post-match trying to recover and feeling awful."

NY TIMES, THE GUARDIAN