44In deciding whether to exclude information and evidence obtained in contravention of the requirements of EU law, regard must be had, in particular, to the risk of breach of the adversarial principle and, therefore, of the right to a fair trial entailed by the admissibility of such information and evidence. If a court takes the view that a party is not in a position to comment effectively on evidence pertaining to a field of which the judges have no knowledge and that is likely to have a preponderant influence on the findings of fact, it must find an infringement of the right to a fair trial and exclude that evidence in order to avoid such an infringement. Therefore, the principle of effectiveness requires national criminal courts to disregard information and evidence obtained by means of the general and indiscriminate retention of traffic and location data in breach of EU law or by means of access of the competent authority thereto in breach of EU law, in the context of criminal proceedings against persons suspected of having committed criminal offences, where those persons are not in a position to comment effectively on that information and that evidence and they pertain to a field of which the judges have no knowledge and are likely to have a preponderant influence on the findings of fact (see, to that effect, judgment of 6 October 2020, La Quadrature du Net and Others, C‑511/18, C‑512/18 and C‑520/18, EU:C:2020:791, paragraphs 226 and 227).
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