The United Nations children's agency has asked authorities to reopen schools in countries where millions of students are still not allowed to return to classrooms following the COVID-19 pandemic. Eighteen months into the pandemic, schools for nearly 77 million students in six countries continue to be almost completely closed, according to an updated data analysis released today by UNICEF released on Thursday. According to the analysis, Bangladesh, the Philippines and Panama are among the countries that kept schools closed the longest. In total, an estimated 131 million students in 11 countries have missed more than three-quarters of their in-person learning. Around 27 percent of countries worldwide continue to have schools fully or partially closed. Nearly a third of this figure is accounted for by the Philippines, which is fighting one of Asia's worst coronavirus outbreaks and where a new school year started this week. Pupils from the six countries represent more than half of the 131 million students worldwide that have missed more than three-quarters of their in-person learning, UNICEF said. "The education crisis is still here, and with each passing day that classrooms remain dark, the devastation worsens," said UNICEF Executive Director Henrietta Fore. "As classes resume in many countries around the world, millions of students are heading into a third academic year without stepping foot in a classroom," said Fore. "The losses that students are incurring from not being in school may never be recovered." To call attention to the 18 months of lost learning, deferred potential and uncertain future, and to urge governments to reopen schools as soon as possible, UNICEF and partners will close down their digital channels Thursday at 13.00 GMT for 18 hours. School closures have created a shadow crisis for children. Beyond falling behind on their education, many children are missing out on school-based meals and routine vaccinations, experiencing social isolation and increased anxiety, and being exposed to abuse and violence. For some, school closures have led to drop out, child labour and child marriage. Many parents have been unable to continue with their employment while balancing their children's care and learning needs. Some have lost their jobs entirely, pushing their families into poverty and creating a deeper economic crisis. While remote learning has been a lifeline for millions of schoolchildren, access to the technology and the quality of the curriculum have been uneven even within communities and school While remote learning has been a lifeline for millions of schoolchildren, access to the technology and the quality of the curriculum have been uneven even within communities and school districts. Experience shows that schools are not the main drivers of transmission and that it is possible to keep them open for in-person learning. UNICEF urges governments, local authorities and school administrations to reopen schools as soon as possible and take all possible steps to mitigate against transmission of the virus in schools. -- Agencies