Chennai is 8.5 hours ahead of Brasília
Best overlap: 8:30 AM to 9:30 AM in Brasília is 5:00 PM to 6:00 PM in Chennai.
Target 8:30 AM to 9:30 AM in Brasília, which lands at 5:00 PM to 6:00 PM for the Chennai side. The overlap barely stretches to 1 hour, so reserve it for what really needs a live conversation and handle the rest async.