The Chemical Weapons Convention (CWC), which entered into force in 1997, introduced a ban on all chemical weapons and stipulates their phased destruction. With 192 States parties, the Convention has now come close to reaching universal effect. The Director General of the Organisation for the Prohibition of Chemical Weapons (OPCW) in The Hague, Ahmed Üzümcü, was re-elected for a further period in office at the Conference of States Parties in December 2013. On December 10, 2013, the OPCW was awarded the Nobel Peace Prize. The use of chemical weapons in the Syrian civil war, for the first time on August 21, 2013 is the biggest challenge for the CWC in its history. The Security Council of the United Nations decided with Resolution 2118 from September 27, 2013 that Syria is obliged to completely destroy its chemical weapons arsenal by June 30, 2014. By the end of 2013, Syria had acceded to the CWC and agreements were concluded according to which Austria provided air transport capacities for the Joint Mission to verify the disarmament process as well as an expert to support it at OPCW headquarters at The Hague. Although the destruction of the chemical weapons arsenal of Syria has largely been completed, poison gas (mainly chlorine gas) was repeatedly used in the Syrian civil war also in 2015, as confirmed by the fact-finding mission set up by the Director-General of Organization for the Prohibition of Chemical Weapons (OPCW). On 7 August, the UN Security Council adopted resolution 2235, by which a Joint Investigative Mechanism was established to ascertain responsibility for these incidents. The Joint Investigative Mechanism produced four reports in 2016, naming Syrian governmental forces responsible for three cases of chlorine gas attacks, and naming IS forces responsible in one case of mustard gas attacks in 2015. On 4 April 2017, once more several dozens of civilians were killed in a chemical weapons attack – most likely using sarin gas.