Seoul City will host a major international gathering on climate change in the middle of May.

Some 500 officials will take part in the C40 gathering set to start May 18th. The C40 is a group of the world's largest cities who have pledged to tackle climate change.

Mayors from Paris, London and Toronto as well as dignitaries from some 80 other cities are expected to participate in the four-day event in which participants are expected to review the results of various measures implemented to fight climate change.

Former U.S. President Bill Clinton, the chief director of the Clinton Foundation, is scheduled to deliver a keynote speech.

The foundation is a leader in the fight against climate change.