One country, one clock

India spans almost 30 degrees of longitude — roughly the same width as the continental United States, which runs four time zones. India runs one. The political reasoning in 1947 was national cohesion; the practical effect is that sunrise in Arunachal Pradesh (northeast) happens around 4:30am while Mumbai's sunrise is closer to 6:30am. For business scheduling this is invisible: if you're meeting with "India," you're meeting with UTC+5:30, full stop. A few researchers and a long-running petition lobby for a second zone for the northeast, and neither has changed policy.

Mumbai business hours and the financial calendar

Mumbai is India's financial capital. The BSE and NSE open at 9:15am IST and close at 3:30pm IST — a short trading day by global standards. Most Mumbai corporate offices run 9:30am to 6:30pm, but the tech sector in Bangalore, Pune, and Hyderabad routinely schedules Western-facing calls as late as 11pm IST to catch the US morning. The phrase "graveyard shift" in Indian IT usually means 9pm–6am IST, sitting alongside North American working hours on the other side of the world.

Scheduling between India and the US

India and the US East Coast have a 10.5-hour gap in winter (ET+10:30 = IST) and 9.5 hours in summer. That makes 7:30–9:30pm IST the only clean window for a live call with New York business hours. For the West Coast, add three hours: an LA morning call typically lands in the Indian evening, not morning, so 9am PT is 10:30pm IST — late but just workable. The half-hour offset catches people off guard: "noon Pacific" becomes "12:30am IST the next day," not midnight. Always write times out in both zones when scheduling.