Chennai is 2.5 hours ahead of Kyiv
Best overlap: 8:00 AM to 4:00 PM in Kyiv is 10:30 AM to 6:30 PM in Chennai.
Target 8:00 AM to 4:00 PM in Kyiv, which lands at 10:30 AM to 6:30 PM for the Chennai side. That's a roomy 8 hours of common time each day, so finding a slot that suits everyone is rarely a problem. For part of the year the maths changes: Kyiv observes daylight saving, Chennai does not, shifting the overlap by an hour.