Please tell that what is constructed on your ground floor bathroom.
3 sides made of bricks and one side project to outside area . small bathroom window made on this wall but still ventilation less. It is not possible to make big window as it is a bathroom. So is there any way to put more ventilation other than window.
I understand your problem, you should fix ventilator from the 4'-6'' height to the roof. By this way you will get maximum posible ventilation. Also made ventilator on door top up to roof/ceiling.