An EFL
is in a country where English is not the dominant language. Students share the same language and culture. The teacher may be the only native English speaker they have exposure to. Outside of the classroom students have very few opportunities to use English. For some, learning English may not have any obvious practical benefit. Students have limited exposure to English-speaking culture, most often through a distorted lens like TV or music.
EFL students will usually all be from the same country. They will have the same culture and make similar mistakes in the target language. Therefore, these mistakes can be rectified by the teacher as a whole rather than individually with the ESL learner