Pressure Relief Vent
WARNING: This page is about a different car, the 2004 Suzuki Swift + and 2004 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.
When all the windows are closed and the ventilations system is ON, the addition of outside air to the interior of the vehicle causes a positive pressure within the vehicle. In order to relieve the pressure, air is released through 2 pressure relief vents. The pressure relief vents are located at the rear quarter of the vehicle, behind the bumper fascia.