Some tips to help-
Use the Info view to find out how much pollution you have.
1. Just use wind turbines for your power as they produce no pollution.
2. Make sure your water source is well away from any pollution.
3. Have no industrial zones, use office zone to keep your
Industry bar happy.
4. When you reach the rank of 'Big town' you will have access to the Incineration plant. Build 3 or 4 of these close to your landfills. Use your inspection tool on all the landfills you own and start emptying your landfills, it'll send them to the incinerators. (Landfills will NOT recieve any rubbish while in emptying mode).
5. When you reach the rank of 'Big City' you will have access to the water treatment plant, bulldoze any water drain pipes you have and replace them with these.
6. Hopefully now the only thing you have left producing pollution is now the Incinerators. Now we can bulldoze them. It'd be advisable to activate the Recycling policy as the pollution will take a few in-game months to disappear. (This is because we have no way of emptying your populations garbage).