Annulment of the votes received at a particular polling station 534. The grounds for nullifying the vote at a polling station can be classified according to the following three groups: (a) irregularities in the composition of the polling station officials; (b) irregularities in the voting process; and (c) irregularities in the vote count or in the protocols or minutes. Irregularities in the composition of the polling station officials 535. In general, illegality in the setting up of the polling station staff is a ground for annulment. The composition of the polling station staff may be unlawful due to flaws in the selection or designation of the polling officers or because their members are not those officially appointed; due to their being appointed after the legally established time limits; or due to there being fewer members than the number allowed. Another cause of annulment of the vote received at a polling station is when it has been set up without justification at a location other than the one authorized. 536. In Colombia, if spouses or close relatives of the candidates have participated as polling officers in charge of the vote count, the votes cast for the candidate in question at that polling station are annulled. Irregularities in the voting process at the polling station 537. Among the grounds for annulment due to irregularities in the voting process provided for in many legal frameworks, the following merit special mention: • when the electoral register at the polling station turns out to be false, falsified or altered; • when there are errors on the ballot papers related to the names of the candidates or the parties’ emblems; • when persons with the right to vote have been impeded from doing so; • when a person who does not appear in the electoral register or whose identity is not verified has been allowed to vote; • when multiple voting has been detected; and • when monitoring by the political parties’ representatives has not been allowed. 175 7. Basic elements of EDR systems frameworks associate a high number of null votes with the possibility of annulling the entire vote at a particular polling station, or even an election as a whole. For example, this could be the case if there are more null votes than valid ones at a given polling station, if the null votes account for more than half the votes cast in the respective election or if two-thirds of the votes cast are either null or blank.