Explain how catalytic converters, Corporate Average Fuel Efficiency (CAFE) standards, and ethanol reduced air polluting emissions from vehicles.

Catalytic converters are used as an exhaust emission control device and are used to remove toxic gases and products by catalyzing the redox reactions.

The Corporate Average Fuel Efficiency (CAFE) standards were set of rules enacted in the USA to increase the efficiency of fuel engines and hence to reduce the emission rates.

The ethanol as compared to the conventional gasoline emits 50 per cent or lesser greenhouse gases to the environment.