The idea of externality was first evolved by market analyst Arthur Pigou in the 1920s.[2] The prototypical illustration of a negative externality is natural contamination. Pigou contended that an assessment, equivalent to the peripheral harm or minor outer expense, (later called a "Pigouvian charge") on bad externalities could be utilized to decrease their rate to a productive level.[2] Subsequent scholars have discussed whether it is desirable over charge or to direct negative externalities, [3] the ideally effective level of the Pigouvian taxation, [4] and what variables cause or worsen negative externalities, for example, giving financial backers in enterprises restricted responsibility for hurts committed by the corporation.[5][6][7]