The Third World is the less developed part of our planet. Levels of economic development and also of education are relatively low in the Third World. Well Third World people tend not to understand the Scientific method and far too many people there believe religions and/or superstitions of different kinds.
Some Third World people believe one or other of the major world religions, Christianity, Islam, Buddhism, Hinduism, Sikhism. Other Third World people believe local indigenous religions dealing with Gods or Spirits.
Education standards are rising in the Third World so in time Third World people may become more skeptical over religion.