India's adoption of Indian Standard Time (IST) 120 years ago marked a shift from local, sun-based timekeeping to a standardized, clock-driven modern life. Historically, time was measured by natural phenomena like the sun, water, or incense, with ancient civilizations developing diverse methods. Today, India maintains highly accurate time through atomic clocks at the National Physical Laboratories, utilizing caesium atoms for precision down to the nanosecond, a stark contrast to earlier systems and essential for modern technologies like GPS.