India, Pakistan and other nations in the Himachal region are overdue for one or more massive earthquakes that could imperil 50 million people and cause an unprecedented loss of life, scientists said. Writing in the journal Science, geophysicists Roger Bilham and Peter Molnar of the University of Colorado and Vinod Gaur of the Indian Institute for Astrophysicist in Bangalore analysed geological evidence and examined historical records regarding earthquakes in the region.