1.
If there is ~ in a place, the place is extremely crowded and blocked with traffic or people.
The problems of traffic ~ will not disappear in a hurry...
N-UNCOUNT: usu with supp, oft adj N
2.
Congestion in a part of the body is a medical condition in which the part becomes blocked. (FORMAL)
...nasal ~.
N-UNCOUNT: usu with supp, oft adj N