This article was copied from SC4ever.com. This article originally created by Bernard.
You begin by making a graduated income tax by setting residential $$% higher than $%, and $$$% higher than $$%. Then you do the same thing for commercial. Next, your eyes move down to Industrial.
Now think. Low income residents have less education, and will work in dirty or manufacturing industries. The $$$ residents usually have an excellent education, and always prefer high-tech industry.
The result; you will NEVER see a dirty or manufacturing industrial building be more than $$, and high-tech buildings are ALWAYS $$$.
What does this tell you? It means that to tax $$$ industry higher than $ or $$ industry results in less demand for high-tech. If you want high-tech industries, you must lower the $$$ industrial tax. To discourage polluting industries, raise the $ and $$ industrial taxes.
This brings us to another point. If you want to force dirty industry to leave your city forever, raise the $ and $$ to an insanely high number. Just make sure that there is enough high-tech demand to replace most of the other industry, or you will be left with no industry. Also, remember to destroy the abandoned buildings if you have the simoleons, because they still pollute.