An earthquake of the magnitude 6.9 on the Richter scale occurred in Sikkim and the neighbouring states of West Bengal, Assam, and Bihar on September 18, 2011. The tremors were felt in five other Indian states, besides affecting neighbouring Nepal, Bhutan, Bangladesh, and China. Although few lives were lost (111 in all) despite the high magnitude of the quake, primarily because its epicentre was in the remote and thinly-populated area of Mangan, significant lessons were learnt in its aftermath.