The Beginning of Indian Standard Time (IST)

Since the Earth rotates on its axis, day and night occur at different times across countries. When it’s daytime in India, it’s nighttime in the U.S. To maintain uniformity, each country follows its own standard time.

After India’s independence, the Indian Standard Time (IST) was established, set 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT). Clocks in major cities like Kolkata, Mumbai, Delhi, and Chennai were synchronized. The National Physical Laboratory in Delhi houses an atomic clock, which serves as the reference for all clocks in India. Today, this system is linked with the Global Positioning System (GPS).