Customs tariff amendment substitutes tariff classification for a specific entry and adds new schedule entries with retrospective effect. The clause substitutes the tariff heading entry opposite Sl. No. 43 in column (2) with '7210, 7212' and declares that substitution to operate retrospectively from 1 March 2011, and further amends the Second Schedule as specified in the Fourth Schedule by inserting new entries 9A, 23A, 23B, 24A and 24B.