Wiktionary
depollute
vb. (context transitive English) To free from pollution.
Usage examples of "depollute".
Blown around by the winds of the world, it should be able to depollute the atmospheric envelope of the planet.
On the one hand we're admonished to clean up our act country-wide, to depollute and let the world breathe, and on the other we're encouraged to ruin our lungs!