Indian chess Grandmaster Vidit Gujrathi has sparked a debate about India's single time zone. "Arrived in Kolkata...it was quite dark around 5.30 pm already. I'm sure there must be...advantages of IST...but isn't there a loss of productivity?" he wrote. "Not if people and organisations are free to choose...working hours," a comment read while another comment read, "We need 3 timezones."