The date was chosen to commemorate the day the Chemical Weapons Convention was entered into force in 2005.
UN Secretary-General Ban Ki-moon spoke Tuesday about the universal need to eliminate all chemical weapons.
The UN head reflected that this year's commemoration of victims of chemical warfare was especially poignant after the use of chemical weapons during the Syrian civil war in 2013.
"The use of chemical weapons in Syria was a deplorable offense against humanity," the secretary-general declared.
"I take this opportunity to reiterate that any use of chemical weapons under any circumstances would be a grave violation of the 1925 Protocol and other relevant rules of customary international law.
"I also reiterate the importance of the 1997 Chemical Weapons Convention. Six countries remain outside the Convention: Angola, Egypt, Israel, the Democratic People’s Republic of Korea, Myanmar and South Sudan.
"Until membership is universal and the last stockpiles of chemical weapons are destroyed, our work will not be done. We must not relax our vigilance. We must do our utmost to deter any future incidents."
On Sunday, the Organization for the Prohibition of Chemical Weapons announced that Syria has removed more than 92% of its chemical weapons material. Investigations into recent
The OPCW announced Tuesday that inspectors will be dispatched to Syria to investigate recent claims that chlorine gas was used in a bombing of two villages, held by rebels, in northern Syria.