Simplify the following text for a Grade 10 native English-speaking person.
Original: On March 16 , 2011 , at the 33rd Session of the World Meteorological Organization 's Regional Association Hurricane Committee , the WMO retired two names , Igor and Tomas , from its rotating name lists .
Simplified: On March 16 , 2011 , World Meteorological Organization retired the names Igor and Tomas from its rotating name lists .