Iranians uphold the time-honored tradition on the thirteenth day of Nowruz by spending the day outdoors.
‘Sizdah’ means thirteen, and 'bedar' means to get rid of, bearing the meaning of ‘getting rid of thirteen’. Sizdah-bedar also marks the end of Nowruz celebrations, which begin on the first day of spring.
A ritual performed at the end of the picnic day is to throw away the "sabzeh" from the Nowruz's “Haftsin table”. The sabzeh is supposed to have collected all the sickness, pain and ill fate hiding on the path of the family throughout the coming year.
Preserving the environment is also an integral part of what Iranians do on Sizdah-bedar.