Customs tariff amendments expand and clarify import duty exemptions for telecom, mobile handset components and aircraft maintenance parts. The notification amends tariff table entries to add and modify exempted imports-including silica preforms for optical fibre manufacture, chargers/adapters and batteries for handset manufacture, and detailed parts and sub parts for populated printed circuit boards-while excluding populated printed circuit boards from generic parts descriptions. It revises aircraft maintenance exemptions by substituting an Annexure condition requiring DGCA approved quality manager certification, maintenance of import/use accounts, periodic submission to the Commissioner of Customs, and execution of a bond to secure duty where goods are not proved to have been used, installed or consumed for permitted maintenance purposes; it also provides an export after repair qualification for imported aircraft components.