The World Health Organization Thursday certified as polio-free 11 countries in Asia that together are home to a quarter of the global population. Bangladesh, Bhutan, South Korea, India, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand, and Timor-Leste constitute WHO's South-East Asia Region. This is the fourth of six WHO regions to be certified, marking an important step towards global eradication of polio. With this step, 80 percent of the world's population now lives in certified polio-free regions, the health agency said in a news release. "This is a momentous victory for the millions of health workers who have worked with Governments, non-governmental organizations, civil society and international partners to eradicate polio from the region," Poonam Khetrapal Singh, regional director for the WHO South-East Asia Region, said in the release. Before a region can be certified polio-free, several conditions must be satisfied, such as at least three years of zero confirmed cases to detect, report, and respond to imported cases of poliomyelitis, and assurance of safe containment of polioviruses in laboratories. WHO noted that polio eradication programs, through their networks and knowledge in reaching the "unreached," have strengthened the delivery of health services to the most vulnerable communities. "Thanks to polio eradication, we now know where these children are who were difficult to reach with vaccine," Dr. Khetrapal Singh said. "Now the polio program has successfully reached them with polio drops in every round, there is no excuse not to go back with other critical health services, from how to have a safe birth, to where to get access to tuberculosis treatment and how to prevent HIV infection."