Introduction
Zarthost No Deeso is an occasion of mourning observed by the Zoroastrians (Parsis). Zarthost No Deeso falls place on June, ( Khorshed roz, Dae mah 11th day, 10th month) of the Zoroastrian calendar.

Legends
Zarthost No Deeso is observed since it is commonly acknowledged that the prophet Zoroaster, founder of Zoroastrianism passed away in a temple when he was praying. It is marked as a solemn occasion. According to another version, Zarathushtra in his 77th year was killed in a fire-temple by the Turanian army. It is also said that on this day, Zarathushtra ascended for the skies.Other sources belive that Zarathushtra died in his sleep or was killed by a murderer.

Rituals of Zarthost No Deeso
Special prayer sessions are organized and prayers are recited with religious discourses focusing on the life and works of the Prophet. Zoroastrians visit the Fire Temple to pray. Marked as a solemn occasion, elaborate celebrations and public functions are largely absent. Even religious ceremonies and services are confined to the temple or homes.

In India, Zarthost No Deeso is particularly observed in Mumbai, Gujarat and other areas with a Parsi population.