1. Leaves are given to employees so that the employees can spend some time with their loved ones.
2. PL (Privilege Leave) is calculated on the the pro rata basis. PL is credited according to no. of days worked in the previous year. CL (Casual Leave) & SL (Sick Leave) are given as per the Company's policy. PL, CL & SL are calculated on the basis of the calendar year.
Also pls see the below links to get your doubt clear...
Hope this clears your doubt...
5th September 2012 From India, Mumbai