This World Water Day (22 March 2013) calls for cooperation on transboundary rivers. Among 276 transboundary river basins in the World, it makes sense for  countries in Indian subcontinent and China to consider it seriously. While the international institutions are trying to define a working definition of 'water security', will India be able to secure unhindered access to water for living beings across McMahon line - the source of all perennial rivers flowing through India?