Nigeria's Minister of State for Petroleum Resources and President of the OPEC Conference Emmanuel Ibe Kachikwu (C) leads the 168th Ordinary meeting of the Conference of the Organization of the Petroleum Exporting Countries OPEC at the OPEC headquarters in Vienna, on December 4, 2015. OPEC oil ministers hold their biannual policy-setting meeting amid a supply glut and slumping crude prices, as member Iran readies to rejoin the global oil market. 
AFP PHOTO / JOE KLAMAR / AFP / JOE KLAMAR        (Photo credit should read JOE KLAMAR/AFP/Getty Images)