What's the noun for congesting? Here's the word you're looking for.
congestion
The hindrance or blockage of the passage of something, for example a fluid, mixture, traffic, people, etc. (due to an excess of this or due to a partial or complete obstruction), resulting in overfilling or overcrowding.
(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
“Flanagan wants to write into the law a provision whereby the Commission would give four farms to the four sons of a farmer to the exclusion of any congest.”
“Almost without exception the criticism of tall buildings as the principal congestors of streets and sidewalks is based on guess rather than on actual facts.”