mitigate       
verb [ T ]  formal uk/ˈmɪt.ɪ.ɡeɪt/ us/ˈmɪt̬.ə.ɡeɪt/
 使缓和;减轻(危害等)
to make something less harmful, unpleasant, or bad
  It is unclear how to mitigate the effects of tourism on the island. 还不清楚如何缓解旅游业对这个岛屿的影响。 
 Compare: extenuate