text: Hence, in order to simplify and harmonize temporary admission formalities provided in various Conventions, the Convention on Temporary Admission, i.e. Istanbul Convention, was adopted at WCO on 26 June 1990 and then entered into force on 27 November 1993. Its objectives and principles are:
  To devise a single instrument for the simplification and harmonization of temporary admission formalities, replacing all the existing Conventions or Recommendations dealing solely or principally with temporary admission. The subjects covered by the former Conventions are now covered by the Annexes to the Istanbul Convention.
  Each Annex authorizes the temporary admission of goods imported for a specific purpose, e.g. Annex B.1. covers goods for display or use at fairs or exhibitions. This avoids the need for the drawing up of any future instruments on temporary admission by creating a framework in which new categories of goods needing temporary admission facilities can be incorporated.
  Goods imported duty-free cannot remain indefinitely in the country of temporary importation. The period fixed for re-exportation is laid down in each Annex.
  The goods must be reexported in the same state. They must not undergo any change during their stay in the country of temporary importation, except normal depreciation due to the use made of them.
  Economic prohibitions or restrictions at importation are not applied since they generally relate to goods cleared for home use, thus serving as a national protection measure.