Singapore's Formula One race remains on track for the weekend despite the haze, with organisers offering disposable face masks to patrons.
Masks that cover the nose and mouth can be purchased at merchandise booths, organisers said, adding that they would be keeping tabs on haze readings while the sporting event kicks off on Friday.
"The haze situation is highly changeable not only from day to day, but from hour to hour," a spokeswoman for Singapore Grand Prix said.
The latest air pollution readings and health advisory will be available on the official website and mobile app, and also broadcast on screens and radio during the event.
Singapore and large parts of Malaysia have been blanketed in ash and smoke emanating from illegal burning to clear land for plantations in neighbouring Indonesia.
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