Chennai and Mumbai are in the same time zone. Both cities use Indian Standard Time (IST, UTC+5:30). When it's noon in Chennai, it's also noon in Mumbai.
India uses a single time zone for the entire country. Neither city observes daylight saving time.
Any time works! Since both cities are in the same time zone, scheduling calls is never a problem. Business hours are identical.
Chennai and Mumbai are two of India's largest cities and economic centers. Flights between them take about 2 hours. Mumbai is India's financial capital while Chennai is its automotive and IT hub.