I found good pointer to these fares.
See
http://www.rtwinfo.co.uk/ft/explorerlatest.pdf

This document describes newest rules.

If Circle Indian Fare and Circle Explorer are same,
Circle Indian Fare Rule in http://www.hardlink.com/~markdu/OWFiles/
(eamus wrote above) is OLD and obsolete.

Under new rule, free flight segments within each continent are limited to 4.
Old rule did not have this restriction.
You can purchase additional flight segments within each continet except the continent of origin (same as One World Explorer Fare) under new rule.

Maximum of 20 segments is also applied under new rule.

Circle Indian Fare Rule in above link does not describe this 20 segment limit.