pollute vs upgrade

pollute

verb
  • To violate sexually; to debauch; to dishonour. 

  • To make something harmful, especially by the addition of some unwanted product. 

  • To make something or somewhere less suitable for some activity, especially by the introduction of some unnatural factor. 

  • To corrupt or profane 

adj
  • Polluted; defiled. 

upgrade

adv
  • Up a slope or grade. 

verb
  • To improve, usually applied to technology, generally by complete replacement of one or more components 

  • To replace with something better. 

  • To improve the equipment or furnishings of or services rendered to 

  • To replace a program with a later version of itself, a version having a higher version number or marketed under a more recent product name. 

  • To improve in condition or status. 

noun
  • An upward grade or slope. 

  • An improvement 

  • An improved component or replacement item, usually applied to technology 

How often have the words pollute and upgrade occurred in a corpus of books? (source: Google Ngram Viewer )