78. All packages and overpacks to be transported shall be categorised into category I-WHITE, II-YELLOW or III-YELLOW in accordance with the conditions specified in the Fifteenth Schedule.
79. In determining the appropriate category of a package or an overpack -
(a) both the transport index and the surface dose rate conditions of the package or overpack shall be taken into account and where the transport index satisfies the condition for one category but the surface dose rate satisfies the condition for a different category, the package or overpack shall be assigned to the higher category;
(b) category I-WHITE, II-YELLOW and III-YELLOW shall be regarded as the lowest, medium and highest category respectively for the purpose of paragraph (a); and
(c) the transport index shall be determined in accordance with the procedures specified in the Sixteenth Schedule.
80. Except under the provision of Article 44, a package and an overpack which contains packages to be transported under a special arrangement shall be assigned to category III-YELLOW.