Kolkata is 10.5 hours ahead of New York during standard time (9.5 hours during daylight saving time). When it's 9:00 AM in New York, it's 7:30 PM in Kolkata.
The 30-minute offset exists because India uses IST (UTC+5:30) rather than a whole-hour timezone. India does not observe daylight saving time.
Limited overlap. 8:00 AM - 10:00 AM New York corresponds to 6:30 PM - 8:30 PM Kolkata. Morning calls from NYC can reach Kolkata's evening hours.
Kolkata (formerly Calcutta) is India's cultural capital and a major business hub. Many IT and business process outsourcing companies operate there, requiring regular coordination with US offices.