+xAs Graham says, these are noise-sensitive areas but I am uncomfortable with them existing so far away from their airfield they are concerned with. We are going to review this internally.
One of the reasons may very well be that the area around LIMB (Milano, Italy) is limited in airspace due to the presence of larger airports like Malpensa LIMC and Linate LIML right next to it. The airfield itself is sits in a 2000-ft limited airspace, Class "A" above. So you basically fly at rooftop level most of the time. In that case, such a large Noise Sensitive Area depiction makes sense IMHO.