and eliminating pollution and preserving the stock of available natural resources. Under this sector essential services could be the monitoring and control of pollution (e.g. of air and water) and meteorological phenomena. vi) Civil protection The objective of the civil protection sector is to prevent, prepare for and respond to natural and man-made disasters. The services provided for this purpose can be the activation of emergency numbers and the implementation of actions informing about, containing and responding to emergencies. 4.1.4. Jurisdiction. Pursuant to Article 5(1), each Member State has to identify OES with an establishment on its territory. The provision does not specify further the type of the legal establishment but recital 21 clarifies that such establishment implies the effective and real exercise of activity through stable arrangements whereas the legal form of those arrangements should not be a determining factor. This means that a Member State can have jurisdiction over an operator of essential services not only in cases where the operator has its head office on its territory but also in cases where the operator has for example a branch or other type of legal establishment. This has as a consequence that several Member States in parallel could have jurisdiction over the same entity. 4.1.5. Information to be submitted to the Commission. For the purpose of the review that the Commission needs to carry out in accordance with Article 23(1) of the NIS Directive, Member States are required to submit to the Commission by 9 November, 2018 and every two years thereafter the following information:  National measures allowing for the identification of OES;  The list of essential services;  The number of identified OES for each sector referred to in Annex II and the relevance of those operators for the sector; and  Thresholds, where such exists, used to determine the supply level by reference to the number of users relying on that service as referred to in Article 6(1)(a) or the importance of the entity in accordance with Article 6(1)(f). The review provided by article 23(1), which precedes the comprehensive review of the Directive reflects the importance that co-legislators attach to the correct transposition of the Directive in relation to the identification of operators of essential services to avoid market fragmentation. In order to carry out this process in the best possible manner and the Commission encourages Member States to discuss this subject, as well as exchange relevant experience in the Cooperation Group. Furthermore, the Commission encourages Member States to share with the Commission - if necessary on a confidential basis - the lists of identified operators of essential services (which ultimately were selected) in addition to all the information that 24