Change from ad valorem to specific duty on paper: tariff converted to a specified per tonne charge under statutory authority. Notification No. 8/90 dated 25-1-1990 amends the earlier customs notification of 27 January 1987 by substituting the ad valorem duty on imported paper with a specific per tonne duty, the amendment being made under the authority of section 25 of the Customs Act, 1962 and effected by direct replacement of the rate in the relevant item.