The month-long holiday is observed principally in Muslim-majority countries in Africa and Asia but also by the believers around the world, including the roughly 3.3 million Muslims living in the U.S. During Ramadan, from sunrise to sunset, observant Muslims (with some exceptions, mostly health related) are forbidden to eat or drink (or smoke, or engage in sexual activity) to purify their thoughts and increase their devotion to God.

Different communities follow different protocols for determining when a new month begins. Some communities follow a set lunar calendar, others use scientific observations to make an official decree about the arrival of a new moon, and still, others mark a new month only after the actual sighting ...