One of the sub-aspects of it also seemed to be tradeoffs between kinds of emissions (where driving down one drove up the other). Weren't the cheating VWs extre

One of the sub-aspects of it also seemed to be tradeoffs between kinds of emissions (where driving down one drove up the other). Weren't the cheating VWs extremely fuel efficient (and thus less CO2 emitting), at the cost of emitting something else nasty?