Muharram, the first month in the Islamic calendar, will begin this week as Muslims observe the Islamic New Year most likely on 15 October, depending on the moon sighting. 

The United Arab Emirates (UAE) has declared a public holiday on 15 October for the Islamic new year, also known as the Hijri New Year or Al-Hijra, Gulf News reported.

In Pakistan, the central Hilal Committee or the moon-sighting committee will look for the crescent moon on Wednesday night, which will mark the beginning of Muharram on Thursday, according to Daily Pakistan

The Islamic new year marks Prophet Mohammed's journey from Mecca to Medina in what was the Gregorian year 622 AD, according to Gulf News. The Prophet's journey is referred to as 'hijira'. 

The upcoming Islamic year will be 1437 AH (after hijra). 

The tenth day of Muharram is observed differently by Shia Muslims and Sunni Muslims across the world. 

Shia Muslims mark Ashura on this day as a mourning for the death of Prophet Mohammed's grandson Imam Hussein, who died in the battle of Karbala. 

Many Shiites participate in processions and self-flagellation as part of the mourning. 

However, Sunnis usually observe a day-long fast on this day to commemorate the fasting by Moses to mark the liberation of Israelites from Egypt.