Ha'mara was a Bajoran holiday celebrating the anniversary of the arrival of the Emissary of the Prophets, Benjamin Sisko. Bajorans fasted to show gratitude to the Prophets for sending him to them.
For the Ha'mara of 2372, a Festival of Lights was held in Bajor's capital city. However, Captain Sisko did not attend. (DS9: "Starship Down")