Authorities in several Muslim-majority countries, including Saudi Arabia, declare Thursday as the first day of Ramadan.

Saudi Arabia’s supreme court declared on Tuesday evening that Wednesday would be the last day of the Islamic calendar month of Shaban, which precedes Ramadan, meaning the Muslim holy month will begin the following day, the official Saudi Press Agency reported.

Ramadan is determined by the Islamic lunar calendar, which begins at the first sight of the moon.

Officials in the Palestinian territories and in Egypt also announced that Ramadan would begin on Thursday.

Meanwhile, authorities in Jordan, Algeria and Morocco said they will wait until Wednesday to decide whether Ramadan would start on Thursday or Friday.

Muslims believe that Ramadan is the month in which the first verses of the Quran were revealed to the Prophet Muhammad more than 1,400 years ago.

Throughout the month, observing Muslims fast from just before the sunrise prayer, Fajr, to the sunset prayer, Maghrib.

The fast entails abstinence from eating, drinking, smoking, and sexual relations to achieve greater “taqwa”, or consciousness of God.

Fasting is one of the five pillars of Islam, along with the Muslim declaration of faith, daily prayers, charity, and performing the Hajj pilgrimage to Mecca – the site of Islam’s holiest shrine, the Kaaba – if physically and financially capable.

In many Muslim-majority countries, working hours are reduced, and most restaurants are closed during fasting hours.

Various Muslim-majority nations have a personalised greeting in their native languages. “Ramadan Mubarak” and “Ramadan Kareem” are common greetings exchanged in this period, wishing the recipient a blessed and generous month, respectively.

Last year, fasting across the world ranged from 10 to 20 hours a day.

At the end of Ramadan, Muslims celebrate Eid al-Fitr. In Arabic, it means “festival of breaking the fast”.

Depending on the new moon sighting, Eid al-Fitr this year is likely to fall on April 21.