Night flying restrictions or night-time curfews,[1] including night flight bans, are any regulations or legislation imposed by a governing body to limit the ground-perceived exposure to aircraft noise pollution during the night hours, when the majority of residents are trying to sleep. Such regulations may include restrictions to available flight paths, or prohibitions against takeoffs, or prohibitions against takeoffs and landings, or prohibitions against ground operations (engine runups or taxiing).[citation needed]