Iranians celebrate their new year on the first day of spring, which usually falls on March 19, 20, 21 or 22. This celebration is called "Nowruz" or "Norouz," and it is among the most celebrated Iranian festivities.
Nowruz has been celebrated for more than 3,000 years, tracing its roots back to holy Zoroastrian rituals. A major part of the festivity involves spring cleaning, during which people clean their houses, buy new clothes and flowers, and prepare the feasts to make the event grand and presentable. People originally participated in this practice in anticipation of spirits or guardian angels who they believed shared the celebration with humans. As of 2015, a diverse group of people from different religions and racial backgrounds celebrate Nowruz; however, certain religious groups still regard it as a holy event.