Fuel mileage vs pollution

The pre-emission diesels about 2005 were the best built now with EGR and DEF they are back to near where they were but they burn more fuel and emit more CO2 so green house gas went up only the Nitrous Oxide went down it is a component of smog but was low in a diesel anyway. The tail pipes are clean but that does not mean the engines are polluting less, on the contrary you burn more fuel (uh lets see where does it all go?) The feds and common sense can not be used with a straight face. So now the clean diesels, use more fuel, the fuel now costs more, and you need to buy a new thing called DEF and there is now a whole bureaucracy to support just that with tons of throw away plastic bottles to go along. We are not better off....... The gent that started this thread with his B5.9L has the better engine when compared to the new 6.7L smog proof replacement. My old Cummins L10 looks good except for a little black at the end of the tail pipe, but I get very near 10 MPG with a 40 foot Monaco.