Acid Wastes

The Acid Wastes span most of the Stanix region in south-west Cybertron. They are a blasted, unforgiving landscape; contaminated by neutronic fallout, wracked by earthquakes, freak weather conditions, and of course acid rain.

The neutronic fallout in the Acid Wastes can produce severe allergic reactions in some Transformers.

Marvel The Transformers comics
Four million years ago the insane Decepticon Megadeath detonated five (or possibly six) neutron bombs there, intending to purge Stanix of non-Decepticon life. Instead the bombs blasted a permanent hole in the upper atmosphere, rendering the region essentially uninhabitable.

2015 Robots in Disguise cartoon
According to Grimlock, the Acid Wastes had the best sunsets.

Robots in Disguise shorts
Apparently there are azaleas that grow there.