119. The Human Rights Committee has made the following observations: “discrimination” as used in the Covenant should be understood to imply any distinction, exclusion, restriction or preference which is based on any ground such as race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status, and which has the purpose or effect of nullifying or impairing the recognition, enjoyment or exercise by all persons, on an equal footing, of all rights and freedoms.57 120. When identifying whether a certain situation amounts to discrimination, the crux of the matter is not so much the mere existence of differential treatment, although this is certainly a starting point, but rather a difference in treatment between objects, subjects or circumstances that are for all intents and purposes considered to be in an analogous situation. This then begs the question as to the level of similarity that needs to exist between an alleged victim of discrimination and their comparator in order for a difference in treatment to amount to discrimination. This must be decided on a case-by-case basis, and will fundamentally depend on the purpose or aim of the measure which has led to the alleged discrimination. 121. In this particular instance, the difference in treatment is twofold, firstly based on residency, which accords different rights to resident and non-resident citizens, and secondly, on the nature of work abroad, which accords favourable treatment to persons in government service. 122. In addressing these two issues, the Commission first tackles the submission of the Respondent State that residency does not form part of the prohibited grounds for restriction under the African Charter. In this regard, it should be noted that the list of prohibited grounds under Article 2 of the African Charter is not exclusive, which is evidenced by the inclusion of the term “other status” in addition to the expressly enumerated grounds. The purpose of Article 2 is to regulate differential treatment based on any identifiable criteria, which in this instance would include both residency and nature of work abroad. The Commission further notes the arguments of the Respondent State that the Victims are not refugees and so can voluntarily return to Zimbabwe to vote. In this regard, the Commission is of the view that it need not prompt any discussions as to the status of the Victims, except in relation to residency or nature of work abroad, as the Complainants have not made any submissions claiming to be refugees. 123. In relation to the first tier of distinction, between resident and non-resident citizens, the Commission has already examined this matter in its discussions on 57 Human Rights Committee, General Comment No.25, para 30