Chennai is 13.5 hours ahead of Portland
There is no standard 8-to-6 overlap. Someone joins early or late.
With 13.5 hours between them, Portland and Chennai have no overlap during standard business hours — by the time one team logs on, the other has logged off. The usual fix is an early start for Portland or a late finish for Chennai — pick whichever team has more flexibility. A quick caveat — Portland's clocks move for daylight saving and Chennai's don't, so the times here are right for only part of the year.