Finishing off Chrome Shelled Regios

So releases of One Piece are still super slow, I watched the newest one last night, which was cool even though it did not seem like much happened in it. In the mean time I have just been watching the rest of Chrome Shelled Regios which is an average length anime of 24 episodes. The show is kind of weird, and I do not really understand what is going on in it most of the time. Like why are there massive bugs called contaminoids, and why is the world toxic outside of the cities called Regios which move around on their own? Some things in it just make no sense and are not explained at all which is a little annoying to me, but whatever its still a cool show I suppose.