With the current regulations regarding emissions I wondered if its possible to reduce emissions for a given car.

In simple terms, could you take a car which produces around 110 g/km and reduce these emissions to below 100 g/km???

I suspect the engine might need a reducer in the inlet to reduce mass airflow and hence fueling, and therefore the knock on effect would be a drop in power from the engine.

Any thoughts on this??? would it be possible and would it be very complicated to do???