Chennai is 3.5 hours ahead of Warsaw
Best overlap: 8:00 AM to 3:00 PM in Warsaw is 11:30 AM to 6:30 PM in Chennai.
Shoot for 8:00 AM to 3:00 PM in Warsaw; your Chennai colleagues will see that as 11:30 AM to 6:30 PM. Chennai is 3.5 hours ahead of Warsaw, but you'd hardly notice — 7 hours of shared hours makes this feel like working in neighbouring time zones. For part of the year the maths changes: Warsaw observes daylight saving, Chennai does not, shifting the overlap by an hour.