Building gathering areas in "Ice Age 2" is a very necessary thing to do in the game, because it can reduce heat demand and reduce fuel consumption. However, one thing to note is that residential areas should not be built near industrial areas. Because this will make people in residential areas sick.
What are the disadvantages of building a gathering area in Ice Age 2
Be careful not to cluster areas together haphazardly.
Residential areas that are too close to industrial areas can increase disease and slums, so keep them farther away from the smog-emitting machines in the city.
It's a good idea to have housing and food on one side of the city, and industry and extraction on the other.