pollution (
http://definr.com/pollution)
n 1: undesirable state of the natural environment being
contaminated with harmful substances as a consequence of
human activities
2: the state of being polluted [syn:
befoulment,
defilement]
3: the act of contaminating or polluting; including (either
intentionally or accidentally) unwanted substances or
factors [syn:
contamination] [ant:
decontamination]