How is classification of various mails done by the postal network of India?

The Indian postal network is the largest in the world. It handles parcels as well as personal written communication. Its classification is done in the following manner:

(i) First Class Mail:

Cards and envelopes are considered first class mail and are airlifted between stations covering both land and air.

(ii) The Second Class Mail:

It includes book packets, registered newspapers and periodicals. They are carried by surface mail, covering land and water transport. To facilitate quick delivery of mails in large towns and cities, six mail channels have been introduced recently. These are called:

(a) Rajdhani Channel (b) Metro Channel

(c) Green Channel (d) Business Channel,

(e) Bulk Mail Channel (f) Periodical Channel