Authorities in India's Bihar state have expelled around 600 high school students for cheating in their 10th grade examinations. The pupils used a novel but somewhat dangerous way to get help with their exam papers – their parents scaled the walls of the school building and provided the answers to questions through the windows. Photographs and video footage of this illegitimate technique have gone viral. They show dozens of parents clinging on to whatever they can on the walls to feed information to their children. Some of the parents were three stories up. Teachers found many cheat sheets inside the classroom. Some had been folded up into paper airplanes and thrown threw the window. Over 1.4 million 10th graders are taking the tests this week at more than 1,200 high schools across the state. Bihar's education minister P.K. Shahi told reporters that schools faced a difficult job to ensure exams took place under the strictest of conditions. He said: "It's virtually impossible to conduct fair examinations without the cooperation of parents." He added that it was not possible to monitor all parents who accompany their children to schools and other test centres. The situation regarding parents helping their children cheat has become so prevalent that police officers are posted to each school. However, an official said, "we can't use force to drive away the parents".