Answer :
Final answer:
EVAP systems were mandated on all cars beginning in the 1970s due to the Clean Air Act signed by President Nixon. Catalytic converters were introduced to reduce vehicle emissions and smog in America's cities.
Explanation:
The EVAP (Evaporative Emission Control) systems were mandated on all cars beginning in the **1970s**. President Nixon signed the Clean Air Act in 1970, which required automakers to reduce vehicle emissions. As a result, automakers included catalytic converters on every new car, which helped reduce smog in America's cities.
Learn more about EVAP systems here:
https://brainly.com/question/31842056
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