Leap Second added to Indian Clock to Synchronize with Earth’s Spin An extra second was added to the Indian clock at 5:29.59 hours at the National Physical Laboratory (NPL) on January 1, 2017 as the atomic clock was struck at 23:59:59 the previous night. The ‘leap second’ was added to the Indian clock to synchronize the Indian Standard Time (IST) with the Earth’s Rotational Clock. The atomic