Kazakh authorities, citing safety concerns, scaled back end-of-school-year festivities, known as the last bell. But such efforts failed to head off widespread incidents of violence and mayhem. The school year ended May 25 for the country’s approximately 4 million schoolchildren, including 200,000 graduating high school seniors, according to the Ministry of Education. Increasing rowdiness in previous years prompted officials in April to ban the organization of end-of-school special events, including banquets and car caravans for graduates in honor of the ‘last bell.’ A more subdued celebration,…