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the horses used to work in the countryside transporting the people, the pooop of the horses pollutes the air -
in1765 the people used to travel in the steam machine this vapors contaminatewd the ambient -
the steamboat used to fight and Commerce between countries.
the fuel used affect the air -
The bike used to be used to transportation and today it is still used for sports -
the plane used to transporting troops and arms contamineited the air