We are sole importers of a ophthalmic product which is an orbital implant exclusively manufactured by a company in USA. There are no similar articles produced or manufactured in India or anywhere else in the world. Our query is as follows: We are currently classified under chapter 9021 (3900) our custom duty structure is as follows: Basic Custom Duty 7.5% SHE Cess 2%, 1% Add. Duty 4% With refer to Custom Tariff Act 1975 3(1) since no similar article is prod or manf in India, then why add duty?