Air quality conditions have yet to improve after smoke played havoc during Australian Open qualifying in Melbourne yesterday.
Poor air quality because of bushfires forced qualifying matches to be delayed yesterday morning but they were eventually cleared to go ahead.
The same delay has occurred today with practice called off in the morning sessions.
The hazardous conditions on Tuesday proved a nightmare for players, who united to condemn the decision to let play unfold.
Aussie Bernard Tomic lost in the first round of qualifying for the year's first grand slam, which starts on Monday, and needed medical attention.
"I just can't breathe," he said.
"No air is going in. I'm getting tired so easy," Tomic was heard telling medical staff.
"Is anyone else complaining today?"
"No, it's been okay," said the medic.
There were also troubling scenes when Slovenian Dalila Jakupovic collapsed to the court due to a coughing fit. Jakupovic, ranked No. 180 in the world, was forced to retire from the match which had gone for just shy of two hours.
The Slovenian put the onus on Australian Open officials, saying the conditions weren't right for matches to go ahead.
"I think it was not fair because it's not healthy for us," she said.
"I was surprised. I thought we would not be playing today but we really don't have much choice.
"If they don't put us on the court, maybe we get fined — I don't know.
"It would be maybe better to see if tomorrow is better. They still have time.
"It was really bad. I never experienced something like this and I was really scared. I was scared that I would collapse. That's why I went on the floor. Because I couldn't walk any more. When I was on the ground it was easier to get some air."
Several high-profile players vented their frustration after seeing fellow players suffering, including former world No. 1 Maria Sharapova and Eugenie Bouchard, who were in action on Tuesday.
World No. 5 Elina Svitolina wasn't happy and took aim at Australian Open officials with a scathing tweet.
Belgian player Steve Darcis delivered his own clip after the matches went ahead despite warnings from the Environmental Protection Authority telling Victorians to remain indoors.
Tennis Australia says it will continue to work with their medical team, the Bureau of Meteorology and Environment Protection Authority Victoria scientists when making decisions about whether it's safe to play.
TA says it has installed measuring devices on-site for air quality, with play cleared to continue during the opening round of qualifying.