Singapore Grand Prix organisers are keeping a close watch on the toxic levels of the "unhealthy" smoke haze that has blanketed the city in the past week.
Forest fires and burning land in plantations from nearby Indonesia have produced a smog over Singapore that could threaten next weekend's event if further deterioration ensues.
"There has been a deterioration in the haze conditions in Singapore this afternoon," said the city-state's National Environment Agency in a statement released on Sunday.
"This was due to a confluence of winds over the nearby region that led to more smoke haze from Sumatra being blown toward Singapore.
"Slightly hazy conditions are expected to continue and the prevailing winds are forecast to blow from the southeast or south."
Singapore Grand Prix organisers are closely monitoring the situation and have devised contingency plans in case the haze worsens significantly.
"The plan was formulated and refined with stake holders, government bodies and the Formula One community," the Marina Bay organisers told AFP.
"In the event that the haze causes visibility, public health or operational issues, Singapore GP would work closely with the relevant agencies before making any collective decisions regarding the event."