Several different groups are excused from fasting during Ramadan: pregnant women, people who are mentally or physically ill, and sometimes women who are breastfeeding. Children are not obligated to fast until they hit puberty, although many choose to observe the fast at least part of the month in preparation for later years.
Sometimes political factors can also get in the way of the fast. In China, celebrating Ramadan has been banned by the government in Xinjian province, where ethnic Uighurs practice Islam. Last month, tensions between Uighurs and police forces led to widespread riots resulting in the deaths of some 35 people.