Pollute less, maybe? What does it do to fuel efficiency (I don't know)? They want you to play by their rules. If you don't, they won't hesitate to put you out of business. My point is that these regulatory agencies often say "jump" and you seem to only ask "how high".I think less pollution is better than more pollution, and I know that DPFs and Urea Injection make automotive Diesel engines pollute less...regardless of the politics surrounding climate change.