How can we reduce air pollution caused by the vehicle’s gas emissions?

1. By washing the vehicle’s fuel tank once a month.
2. By keeping the engine and its surroundings clean.
3. It is impossible to reduce air pollution. It is a constant factor in the vehicle.
4. Correct answer: By regular maintenance of the vehicle’s engine and other systems.

WhyPollution from exhaust is reduced by regular maintenance of the engine and other systems.