conflagration vs ethnic cleansing

conflagration

noun
  • A large-scale conflict. 

  • A large fire extending to many objects, or over a large space; a general burning. 

ethnic cleansing

noun
  • The mass expulsion or killing of people belonging to one ethnic group by those of another. 

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