Formula One officials are hopeful this weekend's Singapore Grand Prix will go ahead as scheduled despite dangerous levels of air pollution affecting the city state.
Lewis Hamilton is due to arrive on Wednesday for the sport's spectacular night race – but the championship leader is set to be greeted by a dense cloud of haze.
Forest fires in neighbouring Indonesia have caused air pollution to reach "unhealthy" levels for the first time in more than three years.
In a statement issued on Tuesday, Singapore's National Environment Agency warned that the situation could deteriorate in the next 24 hours, urging people to "reduce prolonged or strenuous outdoor physical exertion".
The race at the Marina Bay Street Circuit is regarded as the most physically demanding on the sport's calendar due to the humid climate.
But bosses say a contingency plan has been established by the race's organisers to cope with the poor air quality.
An F1 spokesperson told the PA news agency: "The Singapore race organisers have covered the issue of air quality in the contingency plan for this year's grand prix alongside stakeholders, government bodies and the Formula One community.
"They have put in place a number of measures, including public information at the circuit and have taken measures to reduce the impact of the haze for the race weekend."
A spokesperson for the Singapore Grand Prix added: "The haze situation is highly changeable not only from day to day but from hour to hour.
"Therefore, it is currently not possible to reliably predict what the PSI level might be over the race weekend.
"We will continue to work closely with all the relevant government authorities to receive the best possible forecasts when they are available."
Hamilton's Mercedes team are understood to be monitoring the situation, but are hopeful it will improve before the action begins on Friday.
Hamilton, who is 63 points clear in the title race, will land in Singapore after launching the latest collection of his fashion label in Milan on Monday night. The five-time world champion has won in Singapore for the past two seasons.
"For a long time, Singapore used to be one of our weakest tracks, but we've made some inroads into that and performed well last year," Mercedes boss Toto Wolff said.
"However, there are no home runs at a track like Singapore: we take absolutely nothing for granted in our approach to the weekend. We are looking forward to a tough battle."