Nowruz is first day of Spring and the beginning of the Iranian year. Nowruz is celebrated on the day of the vernal equinox, on 20th March or the previous / following day depending on where it is celebrated. Nowruz is celebrated and observed by Iranian people as well as several other countries across Asia including Afghanistan, Turkey, Azerbaijan, Georgia, Tajikistan and many more. The new year starts at the moment the Sun crosses the celestial equator and equalizes night and day or exactly when the Earth has completed one cycle around the Sun.
The celebration has its roots in Ancient Iran. Due to its antiquity, there exist various foundation myths for Nowruz in Iranian mythology. The Shahnameh dates Nowruz as far back to the reign of Jamshid, who in Zoroastrian texts saved mankind from a killer winter that was destined to kill every living creature. In the Shahnameh and Iranian mythology, Jamshid is credited with the foundation of Nowruz. In the Shahnama, Jamshid constructed a throne studded with gems. He had demons raise him above the earth into the heavens; there he sat on his throne like the sun shining in the sky. The world’s creatures gathered in wonder about him and scattered jewels around him, and called this day the New Day or Now-Ruz. This was the first day of the month of Farvardin (the first month of the Persian calendar). On Nowruz, families gather together to observe the rituals and celebrate the beginning of the new year.
In addition, it is believed that originally the celebration was the holiest Zoroastrian festival, and Nowruz is believed to have been invented by Zoroaster himself, although there is no clear date of origin. Since the Achaemenid era, the official year has begun with the New Day when the Sun leaves the zodiac of Pisces and enters the zodiacal sign of Aries, signifying the Spring Equinox.
International Nowruz Day was proclaimed by the United Nations General Assembly, in its resolution A/RES/64/253 of 2010, at the initiative of several countries that share this holiday (Afghanistan, Albania, Azerbaijan, the Former Yugoslav Republic of Macedonia, India, Iran (Islamic Republic of), Kazakhstan, Kyrgyzstan, Tajikistan, Turkey and Turkmenistan.