Excise tariff amendment updates per tonne exemption entries, altering specified table entries in the governing notification. The government, invoking its statutory power to amend notifications, substitutes the column (4) entry for S. No. 29 and the column (4) entry for S. No. 37 in the Table to Notification No. 170/88 Central Excises with a new per tonne rate as a further amendment under the Central Excises and Salt Act.