ZAMBOANGA/MANILA, 18 September 2013 (IRIN) – Aid workers are struggling to provide assistance to more than 100,000 people displaced by fighting in Mindanao, a crisis that could undermine Philippine President Benigno Aquino’s efforts to bring peace to the country’s turbulent south. “There are reports that some of the evacuation centres are overcrowded, and there are serious WASH [water, sanitation and hygiene] concerns, as well as access issues to non-food items,” confirmed David Carden, head of office for the UN Office for the Coordination of Humanitarian Affairs (OCHA) in the Philippines. “We need to ensure that sufficient assistance is available to all those…