How to deletes the backup which are no longer needed?

DELETE Commands :
=================
Delete commands delete/remove specific items from the server, repository catalog.

$ rman

Recovery Manager: Release 11.2.0.1.0 - Production on Fri Dec 27 22:07:16 2013

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RMAN> connect target /;

connected to target database: PROD (DBID=246965557)
RMAN> delete obsolete;

RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=9 device type=DISK
Deleting the following obsolete backups and copies:
Type                 Key    Completion Time    Filename/Handle
-------------------- ------ ------------------ --------------------
Backup Set           1      27-DEC-13
  Backup Piece       1      27-DEC-13          /d01/oracle/flash_recovery_area/PROD/backupset/2013_12_27/o1_mf_ncnnf_TAG20131227T220955_9cvcbwhr_.bkp
Backup Set           2      27-DEC-13
  Backup Piece       2      27-DEC-13          /backup/rman/prod/c-246965557-20131227-00

Do you really want to delete the above objects (enter YES or NO)? yes
deleted backup piece
backup piece handle=/d01/oracle/flash_recovery_area/PROD/backupset/2013_12_27/o1_mf_ncnnf_TAG20131227T220955_9cvcbwhr_.bkp RECID=1 STAMP=835308596
deleted backup piece
backup piece handle=/backup/rman/prod/c-246965557-20131227-00 RECID=2 STAMP=835308597
Deleted 2 objects


RMAN>

Note: -
The above command deletes all the backups that are older based on the retention policy setup.