congestion

An accumulation or buildup, the act of gathering into a heap or mass.

(medicine) Blocking up of the capillary and other blood vessels, etc., in any locality or organ (often producing other morbid symptoms); local hypermic, active or passive

An excess of traffic; usually not a complete standstill of traffic, so usually not synonymous with traffic jam.

(medicine) An excess of mucus or fluid in the respiratory system; congestion of the lungs, or nasal congestion.

edema, water retention, swelling, enlargement of a body part because of fluid retention in tissues and vessels