Chennai is 2.5 hours behind Beijing
Best overlap: 11:00 AM to 6:00 PM in Beijing is 8:30 AM to 3:30 PM in Chennai.
Your shared working hours run 11:00 AM to 6:00 PM in Beijing (8:30 AM to 3:30 PM in Chennai). With 7 hours in common, treat scheduling almost as if the two cities were in the same region.