The Counter For This Goes Up When You Use The "Trickle" God Power On A Building That Is On Fire.
- Firestorm (Natural Disaster) Will Get You 5-6/20 Pretty Much Every Time.
What Won't Help:
- Doesn't Seem To Count Towards Progress If You Light A Building On Fire Yourself, Then Put It Out.
- Putting Out Forest Fires Doesnt Seem To Count Either.
Acheivement Pops When You Put Out 20 Total Building Fires.
Good Luck!