Lastly, we come to section 19 which is the charging section and is in these terms " An excise duty or countervailing duty, as the case may be, at such rate or rates as the State Government shall direct may be imposed either generally or for any specified local area, on any excisable article (a) imported in accordance with the provision of sub section (1) of section 9; or (b) exported or transported in accordance with the provisions of section 10; or (c) manufactured under a license granted in accordance with the provisions of section 14 or section 15; Provided that (i) duty shall not be so imposed on any article which has been imported into India and was liable on such importation to duty under the Indian Tariff Act, 1894 or the : 403 Explanation Duty may be imposed under this section at different rates according to the places to which any excisable article is to be removed for consumption, or according to the varying strengths and quality of such article.