For Shi'a Muslims, Ashura, the tenth day of Muharram, marks the climax of the Remembrance of Muharram, and commemorates the martyrdom of Hossein ibn Ali, the grandson of Muhammad (PBUH) at the Battle of Karbala on 10 Muharram in the year 61 AH ( October 10, 680 CE). This year Ashura falls on Oct 12.
The massacre of Imam Hossein with a small group of his companions and family members had a great impact on the religious conscience of Muslims, particularly Shia Muslims, who commemorate his martyrdom with sorrow and passion, according to IRNA.
Mourning for Imam Hossein and his companions began almost immediately after the Battle of Karbala by his surviving relatives and supporters.
In Iran, Afghanistan, Iraq, Lebanon, Bahrain, and Pakistan, the commemoration of Imam Hossein has become a national holiday and most ethnic and religious communities participate in it. In India, Ashura is a public holiday due to the presence of a significant Indian Shia Muslim population (2-3% of total population, 20-25% of Indian Muslim population).
EghtesadOnline: Millions of Shia Muslims in Iran and other Islamic countries pour into streets, mosques and other religious centers to mark the tenth day of Muharram and mourn for the sufferings of Imam Hossein (AS), the third Imam of Shia Muslims.