Annual Leave Policy - India

Is it common to state in the annual leave policy that there is a carryover of days? If so, how many days is most common.
Is it common to state that there is encashment of unused annual leave days? If so, how many days are typically allowed for carryover or accumulation.

Question 1:
Is there is any option of not to carry forward annual leaves to next year... if any like that mentioned in policy.. please let me know the same..
Question 2:
If carry forward options is there for annual leave, please let me know how many leaves max. can be carry into next year...
Regards,
Venkata Krishnan R