custom Duty is imposed under the Indian Customs Act formulated in 1962 by the Constitution of India under the Article 265, which states that “no tax shall be levied or collected except by authority of law. So, the Indian Custom Act was introduced that allow the Central Government to collect the taxes under the name of Custom Duty.
Custom Duties are usually levied with ad valorem rates and their base is determined by the domestic value 'the imported goods calculated at the official exchange rate. Similarly, export duties are imposed on export values expressed in domestic currency.