maybe, but its cleaner in other ways. It burns hotter and more efficiently, creating less CO2 and some other byproducts by a decent margin. It produces more SO due to fuel sulfur content, and more NOX which is produced because of high temperatures. So its a trade-off.

But at this point the limits are just politicians pulling levers. There's not enough science involved to debate which pollutants we care about and what the lowest realistic limits are.