Chennai is 9.5 hours ahead of Atlanta
Best overlap: 8:00 AM to 9:00 AM in Atlanta is 5:30 PM to 6:30 PM in Chennai.
If you set up a recurring sync, 8:00 AM to 9:00 AM in Atlanta (5:30 PM to 6:30 PM in Chennai) is the natural home for it. Chennai is 9.5 hours ahead of Atlanta, so you only get about 1 hour of overlap a day — worth locking in a standing time like 8:00 AM in Atlanta (5:30 PM in Chennai) before it slips. Because Atlanta and Chennai don't both observe daylight saving, plan to re-check the overlap around March and November.