Singapore, Oct. 3 -- Formula 1's governing body has classified this weekend's Singapore Grand Prix as a "heat hazard" race for the first time, as soaring temperatures and high humidity threaten to push drivers to their physical limits.

The ruling by the FIA was triggered by forecasts of 31 degrees Celsius and oppressive humidity in the tropical city-state. Under the regulation, teams must equip their cars with driver-cooling vests, although using them is optional.

The measure ensures that competitors who decline to wear the vests do not gain a performance edge from a lighter car.

It is the first time the FIA has invoked the new heat-hazard provision, introduced after the 2023 Qatar Grand Prix left several drivers requiring medical treatm...