AMD device routing architecture comprises interconnect resources of various lengths in each direction: North, South, East, and West. A congested area is reported as the smallest square that covers adjacent interconnect tiles (INT_XnYm) or CLB tiles (CLE_M_XnYm) where interconnect resource utilization in a specific direction is close to or over 100%. The congestion level is the positive integer which corresponds to the side length of the square. The following figure shows the relative size of congestion areas on an AMD device versus clock regions.
Figure 1. Congestion Levels and Areas in the Device View