(1)For the purpose of preferential treatment in sorting transmission and delivery, postal articles are divided into the following four group in the following order namely:-(a)Postcards, Letter cards, Money orders and standard envelopes as defined in sub-rule (4) of rule 8.(b)Letters (other than standard envelopes as defined in sub rule 4 of rule 8) and surcharge air-mail articles.(c)Standard articles as defined in sub-rule (5) of rule 8;(d)all other postal articles.(2)Postal articles of any of the groups above may be detained in sorting, transmission or delivery if it is necessary to do so to expedite the sorting, transmission or delivery of postal articles in the group or groups higher in the preferential order mentioned in sub rule (1)Vide GSR 965 dated 12/12/1989
