People using 'less' when they should be using 'fewer'
EDIT: you guys have dug up some truly horrible pisstakes :D Thank you for those.
To the serious folk - relax a little. This is Mildly Infuriating, not I'm dying if this doesn't stop. As a non-native speaker I was taught a certain way to use the language. The rules were not written down by me, nor the teachers - it was done by the native folk. Peace!
That's exactly the point. There's nothing pedantic about acknowledging the difference. "Fewer" is for a countable number of things like "pollutants", and "less" is for uncountable things like "pollution". It's not hard.