Five years absence is considered a resignation

New Delhi, Mar 30, 2012(PIB): The CCS (Leave) Rules has been amended by the Department of Personnel and Training (DOPT) vide Notification F.No.13026/2/2010-Estt.(L)] dated 29.03.2012.

You can't take leave excess five years.

According to the new amendment, the Government Servants cannot be granted any kind of leave for a continuous period more than 5 years.
It has been further laid down that any government servant if absent from duty for more than 5 years continuously with or without leave (other than on foreign service), they shall be deemed to have resigned from their post.
The said notification is placed below for your ready reference.
Click here for the notification.