In the Simple Word, No Seat for Half Fare.
Example: You booked Ticket for child between 5 to 11 Yrs, In the status of seat NOSB instead of CNF.
NOSB = No Seat Berth (If Child Age Less Than 11 And Opted For ½ Ticket (for Half Fare))
NOSB, 0 = Means allowed for journey without seat.
If you want book Seat you have compulsory Pay Full Fare (Same as Adult Fare) for the Child Even age Between 5-11 Years.
Indian Railway concession rules for child from April 2016
Children Concession Rules Changed from 1st April 2016.
Indian Railways Revised Children Concession Rules
As per the revised rules, full adult fare will be charged for children between 5 and 12 years of age if a berth/seat is sought for them in the reserved class. In case a berth/seat is not sought, half the adult fare will be charged.
There will be no change in the fare of unreserved tickets, and the charges will continue to be half of the adult fare.
The revised rule shall be applicable from April 2016. The exact date of commencement of this provision will be notified separately later, according to a statement issued by the railways.