If you have gone in search of the perfect 1000 city score, you have probably found that the most difficult problem to eradicate is pollution. You need industrial zones but they pollute. Try overlapping industrial zones with Stadiums.
Stadiums continually refresh their display, wiping out portions of the industrial zones.
An industrial zone pollutes less when it is covered by a stadium, but it is not affected otherwise. It still has the same amount of employment positions for your sims. This can help you get much closer to the elusive 1000 goal. Download lowpolut.zip, which contains lowpolut.cty, an example of the above trick.