The Islamic new year, or the Hijri new year, marks the start of the Muslim lunar calendar. The year has 12 months beginning with Muharram, and ending with Dhul al-Hijjah. Each month starts with the sighting of the new moon.
During Muharram (the first month of the Muslim lunar calendar), the tenth day marks Ashura.
For Shia Muslims, Ashura is a day of mourning which commemorates the martyrdom of the Imam al-Husayn (grandson of the Prophet Muhammad). This is considered to be the defining event in Shia history and fasting is discouraged.
For Sunni Muslims, Ashura is a fasting day to remember the day Nuh (Noah) left the ark and the day that Musa (Moses) was saved from the Egyptians by Allah.
Happy Muharram to all our colleagues celebrating today!