Why does your one nostril be blocked?

One nostril may feel blocked due to the natural nasal cycle, where congestion alternates between nostrils every few hours. This cycle is influenced by the swelling and shrinking of the nasal tissues, primarily due to changes in blood flow. Additionally, Allergies, colds, or sinus infections can exacerbate this blockage, causing one side to feel more obstructed than the other. Environmental factors, like dry air or pollutants, may also contribute to nasal congestion.