The first thing is to identify the reasons for attrition. It could be that:
1. Private banks pay better.
2. Working conditions are not congenial.
3. No scope to get immediate promotions, etc.
After you list them out, you may find some are within your control and some are beyond your control. See what best can be done with those under your control. Despite all the above factors, attrition may continue to be there. Consider how quickly you can recruit and train new people.
Regards,
V. Raghunathan
Navi Mumbai