Encourage people to use public transport
Learn how other countries avoid it
Avoid squandering

Be less materialistic
Reduce the number of cars
Recycle more
Avoid buying cars
Encourage people to use more taxis and buses
Be cleaner
Clean the beaches, mountains, etc.
Be more ecological
Pass more laws
Eliminate toxic residues
Encourage people to ride a bike
Eliminate toxic residues
Not use cars
Think more about the rest of the people in the world
Reduce the numbre of cars
Be ecologycal