Ramadan, the first day of the ninth holy month of the Islamic calendar of the same name, began on Tuesday. During this period, Muslims from across the world observe fast and abstain from eating and drinking water from dawn to dusk.
The ninth lunar month is considered the most sacred month of the Islamic calendar, because it was when the Holy book of Quran was revealed to Prophet Muhammad.
It is believed that the practice of fasting and giving charity will bestow blessings upon each person.
The holy month begins after the sighting of the new moon to the naked eye and lasts for 29 to 30 days after the begining of the month.
However, this year saw Muslims begin the fast on different days due to the disagreements over the start of the holy month.
In the US, The Fiqh Council Of North America, an association of Muslims who interpret Islamic law and which is affiliated with the Islamic Society of North America (ISNA), has declared Tuesday as the first day of the holy month Ramadan.
Muslim leaders in northern Paris, Middle Eastern countries, including Saudi Arabia and United Arab Emirates, said on Monday that they would wait till Wednesday to begin the fast as they failed to sight the new moon by traditional direct observation, Reuters reported.
In India, Muslims will begin the month-long fast from Thursday, since the moon was not sighted because of the weather.
"We failed to get any confirmation of sighting the moon," said Liaqat Khan of Darul Uloom Deoband, India's best-known Islamic seminary, according to Hindustan Times.
Ramandan ends on the 29th or the 30th day and concludes with Eid al-Fitr, the festival of fast-breaking. It marks the beginning of the next lunar month - Shawwal. Eid al-Fitr is one of the most important Islamic celebrations in the world.
During Eid al-Fitr, people wear new clothes, decorate their homes, give treats to children, donate food to poor people and visits friends and family.
Scroll down to check the photographs showing the start of the holy month of Ramadan across the world: