Congest and Over-crowding

Congest verb - To prevent passage through by filling with something.

Over-crowding and congest are semantically related In some cases you can replace phrase "Over-crowding" with "Congest", this terms are similar.

Over-crowding noun - Excessive crowding.

Congest and over-crowding are semantically related in crowd topic. Sometimes you can use "Congest" instead a verb phrase "Over-crowding", if it concerns topics such as cram.