Rafael Nadal has insisted that the current smog hanging over Beijing is no different to what players have faced before.
The Spaniard was speaking after progressing to the quarter-finals of an event where conditions have become unpleasant due to a rise in air pollution levels.
On Wednesday, visibility due to smog was cut to just over half a mile in the Chinese capital, and China's National Meteorological Centre issued a yellow alert.
Nadal was reticent to get drawn into criticism of the situation, and said that conditions this week were not the worst he has seen.
"No, nothing new for us. I've played here a lot of times. Was very humid today. I see the pollution this year better than other years," he said.
The 29-year-old added: "Two days ago was a very beautiful day, blue sky. It's true that during the afternoon, seems like the pollution goes down a little bit more. But in the morning was not bad at all."
Caroline Wozniacki echoed Nadal's sentiments, and said that the conditions were not unexpected.
"The pollution, I think we're used to it when we play here," said the Dane. "The good thing is that it's a little colder here than it was (at last week's Wuhan Open).
"You know, we just play. We just play. It's the same for both players. It's a big city, so that's what you can expect."
However, fans attending the event were much more willing to express their displeasure.
"There is definitely danger to the athletes," one spectator told CNN.
"I think either the sponsors or government should have solved this in advance, but neither of them did."