Motorsport's governing body said transboundary haze from Indonesian fires, which pushed air pollution in Singapore into unhealthy levels on Thursday, did not "represent a threat" to this weekend's Formula 1 race in the city-state.
Singapore's air quality again crossed the threshold, making it one of the most polluted cities globally, according to the Swiss-based air monitor IQAir.
"Air quality levels are being monitored by the relevant local authorities, and appropriate contingency measures are in place should conditions worsen," the FIA said in a statement to AFP.
If the haze worsened "and depending on the pollution level, there may be some restrictions on outdoor activity focusing mainly on entertainment activities rather than the Paddock environment and the circuit," the FIA said late on Wednesday.
But "based on the latest information available, air quality and haze are not forecast to represent a threat to track activity or the conduct of the event," it said.
Race organisers too said they were unconcerned about the haze, despite IQAir's website showing Singapore as the world's third most-polluted major city after Kuala Lumpur and Kinshasa, with an Air Quality Index reading of 174.
The AQI converts measurements of pollutants into a single figure indicating air quality and potential health risks.
Readings above 150 are classified as unhealthy, while levels above 300 are considered hazardous.
Singapore's National Environment Agency data showed all five regions in the city-state recorded "unhealthy" levels of air pollution.
Singapore and Malaysia have been surrounded by a milky haze for more than a month as smoke drifted across from uncontrolled fires on Borneo and Sumatra islands.
The possibility of haze is just one of the "many potential issues" that are covered in the overall contingency plan for the race, said Singapore GP in a statement.
In the event that haze causes visibility, public health or operational issues, Singapore GP would work closely with the relevant agencies to assess the situation before making any collective decisions regarding the event," it said.
An F1 spokesperson told AFP, "There is absolutely no risk to the event and the conditions where the event is taking place are not at any level of concern."
The FIA's F1 race director Rui Marques, however, issued a heat hazard on Thursday, saying that both Saturday's sprint and Sunday's race will be run at times in a heat index greater than 31C.