Australian Open organisers have imposed a three-hour delay to the start of qualifying matches on Wednesday because of the "very poor" air quality from ongoing bushfires in the country.
It is the second successive day the start of play has been delayed because of the conditions in Melbourne.
On Tuesday, Slovenia's Dalila Jakupovic had to be helped off court after retiring from her match.
Air quality in the city did improve overnight but is still "unhealthy".
In a statement, Tennis Australia said: "Practice has been suspended until 11am due to air quality concerns, and play won't start before 1pm.