A small section of my city in the corner has been affected by radiation. All the buildings (including shops and houses) now show signs of radioactivity. When I bulldoze them, the radiation disappears, but when the buildings are rebuilt, they are still affected.
I have an Oil Factory right smack in the middle from where the radioactivity is coming from. But even when I bulldoze the Oil factory, the radiation is still there.
How do I get rid the radioactivity?