Some of my houses sit on land that has a kind of grey dotted pattern, the pattern extends over their houses and any village who comes out of the house is already mopy and doesn't perk up when clicked on.
What is it? How can I get rid of it?
That part of the land is a swamp, some also call it blighted land. Your followers inside it move slower and can die if they stand inside it too long.
You can get rid of it with the Beautify spell, which you find later on.
It is the grey. The more your people are in it they begin to die.