Under the patronage of the Custodian of the Two Holy Mosques King Abdullah bin Abdulaziz Al Saud, the 4th International-Gulf Forum and Exhibition on Environment and Sustainable Development under title of \"Investment Opportunities in Renewable Energy and Energy Efficiency and Water\" will begin tomorrow at Four Seasons Hotel in Riyadh.During a three-day event, the forum and exhibition will be supervised by Presidency of Metrology and Environment (PME) and organized by Saudi Environment Association.More than 1,500 searchers in the field of environment and 50 speakers from different countries will participate in the forum.The forum will discuss issues pertaining to energy efficiency, sustainable development and environment.