I tried to write out all the rules! It's hard!
You're drawing routes, splitting them with plazas, using factories that produce pollution to try and populate an island.
When drawing the island just freehand some weird shapes and go from there.
Some details I didn't have room for:
Each factory size (1,2,3) has specific traits.
Size 1 must be drawn exactly as it is, and completely on land.
Size 2 can be horizontal or vertical, and must be partially on water and partially on land. You can build one anywhere legal at any time, but it produces 2 pollution itself to do so! Your first move after setting up a blank island will always be to build a size 2 factory.
Size 3 can be any triomino. Put a little garbage platform next to it or on top of it.
I've really enjoyed the weird space and the islands that result. Let me know if you give it a try? I know this one is significantly more complicated than my last paper playable.