Agence France-Presse: Politicians, corporate executives, engineers and greens gather here on Monday for a week-long arena aimed at tackling the planet’s fast-growing water crisis. Around 20,000 people are expected for the Fifth World Water Forum in the Turkish city of Istanbul, where a charged agenda awaits them. Access to clean water and sanitation, river pollution, madcap extraction of aquifers, jockeying for water rights and the impact of climate change have turned the stuff of life into a …