Chennai and Delhi 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 Delhi.
India uses a single time zone for the entire country despite its large east-west span. 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 Delhi are two of India's major metropolitan cities. Flights between them take about 2.5 hours. Chennai is India's automotive hub while Delhi is the political capital.