# Regulation (EC) No 1987/2006 of the European Parliament and of the Council of 20 December 2006 on the establishment, operation and use of the second generation Schengen Information System (SIS II), Article 21: Proportionality

Extent: E+W+S+N.I.

Before issuing an alert, Member States shall determine whether the case is adequate, relevant and important enough to warrant entry of the alert in SIS II.
Where the decision to refuse entry and stay referred to in Article 24(2) is related to a terrorist offence, the case shall be considered adequate, relevant and important enough to warrant an alert in SIS II. For public or national security reasons, Member States may exceptionally refrain from entering an alert when it is likely to obstruct official or legal inquiries, investigations or procedures.

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Source: https://www.legislation.gov.uk/eur/2006/1987/article/21 (the official version)
Page: https://openlegislation.uk/eu-regulation-2006-1987/article-21
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.