pollution fixing problems

[Twoofsix]

I have a number of dead tiles near my cities. I want to terraform them back into living tiles but even though I have about 10000 public works in reserve I still cannot terraform the dead tiles what is wrong? Do I first need to discover conservation? Or should my government not be Corporate Republic? I'd be grateful for any help.

Twoofsix

[down th' pub]

Yeah, you need Conservation.