Dear Sudhakar Reddy,
Whenever an employee travels for official purposes, whether deputation or otherwise, the travel period has to be considered as "On Duty".
Now suppose, an employee is required to travel from Bengaluru to Delhi for official assignment. On completion of the assignment, he/she asks for the leave. Even in this case also, the time taken for return travel from Delhi to Bengaluru will be considered as on-duty period.
Thanks,
Dinesh Divekar