The clock that never moves
Most US cities shift their gap to India twice a year. Phoenix does not: it stays on Mountain Standard Time, UTC−7, all year, and India stays on UTC+5:30, so 09:00 in Phoenix is 21:30 IST in January and in July. An Indian team can fix its Phoenix shift once and leave it.
The neighbours move around it. In summer Phoenix shares a clock with Los Angeles; in winter it shares one with Denver. If your team serves clients across the West, schedule Phoenix on its own line rather than by 'Pacific' or 'Mountain'.
Twelve and a half hours means the Phoenix working day is the Indian night. Systems carry the updates through it, and people answer in the window: a question sent at 15:00 in Phoenix reaches India at 03:30 IST and can still be answered free-form at 10:00 IST, which is 21:30 the previous evening in Phoenix.
Heat is the other local constant. Phoenix averages 111 days a year at 100°F or more, so an update about a delivery or a site visit is most useful early: sent around 06:00 local time, which is 18:30 IST, it arrives before the hottest hours and before your Indian team leaves.