Exhaust gas recirculation (EGR) was an early and primitive automobile emissions-control device that was used from the late 1960s through the early 1980s. The EGR equipment is sometimes casually referred to as a pollution pump or smog pump, although these terms may also refer to an air injection reactor (AIR) system, another early pollution control method.

It consisted of a small device that pumped exhaust from the engine back into the intake, thereby re-burning the mix and burning off some of the pollution. This was particularly effective during acceleration, when extra fuel/gas mixture, the charge, was pumped into the cylinder and wouldn't burn cleanly.

Pumping hot, dirty air into the cylinder has negative effects on the gas mileage, but the pump was a simple device that could be added to existing engines.

Newer engines have turned almost entirely to fuel injection, which eliminates this problem entirely, and without a pollution pump, the relative gas mileage improves.