TIANJIN, China, June 27 (Reuters) - Ageing populations in developed countries and emerging markets will exert pressure on economic growth, Ngozi Okonjo-Iweala, Director-General of the World Trade Organization (WTO), said on Tuesday.

Speaking at the World Economic Forum's (WEF) 14th Annual Meeting of the New Champions in northern China's Tianjin city, Okonjo-Iweala said the world should be thinking about harnessing the areas where there is productivity growth and where the young labor will help the global economy. (Reporting by Bernard Orr and Ethan Wang; Editing by Kim Coghill)