How can the day of Ashura and its fasting be determined this year, given the uncertainty of when the month of Dhu al-Hijjah began and whether it will be 29 or 30 days?

If the beginning of the month of Muharram is not known, the month of Dhul-Hijjah is completed to thirty days, and the day of Ashura is calculated accordingly. As a precautionary measure, one can fast two consecutive days that cover the two possibilities for Ashura, in case Dhul-Hijjah was 29 or 30 days. This would be either fasting on Tasu'a and Ashura, or Ashura and the eleventh day. To further ensure Tasu'a, one can fast three consecutive days, to include the ninth, tenth, and eleventh, or the eighth, ninth, and tenth. If fasting for only one day is possible, Dhul-Hijjah is completed to thirty days, then the tenth day is fasted. If reliable news comes regarding the sighting of the Muharram crescent, it should be acted upon. Fasting in the month of Muharram is generally recommended.