pollute
v.to make something dirty or harmful by adding bad substances to it. You use this when talking about making the air, water, or soil unhealthy.
v.to contaminate or make impure by the addition of harmful or undesirable substances. Transitive — requires a direct object representing the medium being contaminated.
“Factories often pollute the local river.”
“The government is trying to find new ways to prevent companies from polluting the atmosphere with carbon dioxide.”
“While natural processes can sometimes pollute the environment, human industrial activity remains the primary source of toxic waste in modern ecosystems.”
From Middle English polluten, borrowed from Latin pollūtum, from pollūtus (“no longer virgin", "unchaste”), perfect passive participle of polluō (“soil", "defile", "dishonor”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.