One of the distinctive features of the national leadership of Xi Jinping has been the revival of the mass line in Community Party theory and praxis [REF].
In his own words, Xi has described the campaign in terms of "purification" of the Communist Party, often involving the elimination of "hedonism and extravagance",[REF] although the purification implied is sometimes extended metaphorically to issues such as "reducing air pollution" [REF].