Mitigation rhymes with:
instigation, instigation, abrogation, allegation, congregation, conjugation, delegation, desegregation, elongation, fumigation, instigation, interrogation, investigation, irrigation, ligation, litigation, navigation, negation, obligation, propagation, segregation, surrogation
Mitigation sounds like:
madhusudan, medication, medstone, midgetman, midsection, modestine