1

By its application, the European Commission requests the Court to declare that:

2

Article 3(1) of Directive 91/271 provides:

‘Member States shall ensure that all agglomerations are provided with collecting systems for urban waste water,

and

For urban waste water discharging into receiving waters which are considered “sensitive areas” as defined under Article 5, Member States shall ensure that collection systems are provided at the latest by 31 December 1998 for agglomerations of more than 10000 p.e.

Where the establishment of a collecting system is not justified either because it would produce no environmental benefit or because it would involve excessive cost, individual systems or other appropriate systems which achieve the same level of environmental protection shall be used.’

3

Articles 4 to 7 of Directive 91/271 lay down a series of requirements relating to urban waste water treatment.

4

Article 4(1) of the directive provides:

‘Member States shall ensure that urban waste water entering collecting systems shall before discharge be subject to secondary treatment or an equivalent treatment as follows:

5

Article 5 of that directive states:

‘1.   For the purposes of paragraph 2, Member States shall by 31 December 1993 identify sensitive areas according to the criteria laid down in Annex II.

2.   Member States shall ensure that urban waste water entering collecting systems shall before discharge into sensitive areas be subject to more stringent treatment than that described in Article 4, by 31 December 1998 at the latest for all discharges from agglomerations of more than 10000 p.e.

…

4.   Alternatively, requirements for individual plants set out in paragraphs 2 and 3 above need not apply in sensitive areas where it can be shown that the minimum percentage of reduction of the overall load entering all urban waste water treatment plants in that area is at least 75% for total phosphorus and at least 75% for total nitrogen.

…’

6

Article 10 of that directive provides:

‘Member States shall ensure that the urban waste water treatment plants built to comply with the requirements of Articles 4, 5, 6 and 7 are designed, constructed, operated and maintained to ensure sufficient performance under all normal local climatic conditions. …’

7

Article 15 of Directive 91/271 provides:

‘1.   Competent authorities or appropriate bodies shall monitor:

2.   Competent authorities or appropriate bodies shall monitor waters subject to discharges from urban waste water treatment plants and direct discharges as described in Article 13 in cases where it can be expected that the receiving environment will be significantly affected.

…’

8

The Act concerning the conditions of accession of the Czech Republic, the Republic of Estonia, the Republic of Cyprus, the Republic of Latvia, the Republic of Lithuania, the Republic of Hungary, the Republic of Malta, the Republic of Poland, the Republic of Slovenia and the Slovak Republic and the adjustments to the Treaties on which the European Union is founded (OJ 2003 L 236, p. 33; ‘the 2003 Act of Accession’) provides, in Chapter 8, Section B, point 1(a) of Annex X thereto:

‘By way of derogation from Articles 3, 4 and 5(2) of Directive 91/271/EEC, the requirements for collecting systems and treatment of urban waste water shall not fully apply in Hungary until 31 December 2015 in accordance with the following intermediate targets:

9

On 16 February 2017, the Commission sent Hungary a letter of formal notice, in which it stated, in essence, that the information available to it showed that, on the dates fixed by the 2003 Act of Accession, that Member State did not comply with some of the requirements laid down by Directive 91/271 in respect of a number of Hungarian agglomerations.

10

On 21 April 2017, Hungary replied to that letter of formal notice.

11

Not satisfied with that reply, on 8 December 2017 the Commission sent Hungary a reasoned opinion under Article 258 TFEU, in which it criticised that Member State for failing to fulfil its obligations under Directive 91/271.

12

On 13 February 2018, Hungary replied to that reasoned opinion.

13

Unconvinced by that reply, the Commission brought the present action for failure to fulfil obligations.

14

In support of its action, the Commission relies on four complaints alleging, first, infringement of Articles 3 and 10 of Directive 91/271, second, infringement of Articles 4 and 10 of that directive, third, infringement of Articles 5 and 10 of that directive and, fourth, infringement of Article 15 of that directive.

15

In the first place, the Commission submits that Hungary has not complied with the requirements laid down in Article 3(1) of Directive 91/271 as regards the agglomerations of Békés, of Dabas, of Dunavarsány, of Hódmezővásárhely, of Keszthely, of Kéthely, of Kiskunhalas, of Köröm, of Marcali, of Mezőtúr, of Nagykőrös, of Pilisvörösvár, of Soltvadkert, of Szécsény, of Szentendre, of Szentes, of Szigetszentmiklós, of Tököl, of Tolna, of Veresegyház, of Zalaegerszeg and of Zalakaros.

16

First, the information at its disposal shows that, on the dates set out in Chapter 8, Section B, point 1(a) of Annex X to the 2003 Act of Accession, all those agglomerations used, repeatedly and to a significant extent, individual urban waste water collection systems. In addition, the rates of connection to the collecting systems for that water, where such systems exist, are low in all those agglomerations.

17

Second, the recurring and significant use of individual systems for collecting urban waste water in the agglomerations concerned does not comply with the requirements laid down in Article 3(1) of Directive 91/271. That provision states, in its first and second subparagraphs, that the provision of those agglomerations with collecting systems for urban waste water is the rule and, in its third subparagraph, that it is only where the establishment of such collecting systems is not justified, for environmental or financial reasons, that, by way of derogation, individual collection systems for that water may be used under certain conditions. In the present case, Hungary has never shown that the installation of collecting systems was not justified in the agglomerations in question. Nor, moreover, does that Member State establish that the Hungarian legislation on the use of individual systems for collecting urban waste water makes it possible to ensure that those systems ensure a level of environmental protection identical to that which would be ensured by collecting systems.

18

In the second place, the Commission claims, in essence, that, since the agglomerations concerned are not provided with collecting systems complying with the requirements laid down in Article 3(1) of Directive 91/271, it must therefore be held that Hungary also fails to comply with the requirements applicable to treatment plants under Article 10 of that directive.

19

Hungary contends, in essence, first, that the question whether the requirements laid down in Article 3(1) of Directive 91/271 are met must be assessed at the level of agglomerations, as defined by that directive.

20

Second, the present complaint is based on a misinterpretation of Article 3(1) of Directive 91/271. It follows from that provision that the collection of urban waste water can be ensured not only by collecting systems but also by individual systems. Consequently, even if the collection of such waters constitutes, according to the settled case-law of the Court, a clear and unequivocal obligation as to the result to be achieved, that obligation could be complied with by having recourse to all those systems, provided (i) that the use of individual systems is justified and (ii) that those systems achieve a level of environmental protection identical to that which would be ensured by collecting systems.

21

Third, those various requirements are complied with in the present case.

22

The first complaint may be divided into two parts.

23

As regards the first part of that complaint, alleging infringement of Article 3(1) of Directive 91/271, it should be recalled that the first two subparagraphs of that paragraph require Member States to ensure that all agglomerations are provided with collecting systems for urban waste water by certain dates specified in those subparagraphs. For its part, the third subparagraph of that paragraph states that where the establishment of a collecting system is not justified either because it would produce no environmental benefit or because it would involve excessive cost, individual waste water collection systems or other appropriate systems which achieve the same level of environmental protection must be used.

24

First of all, it follows from the wording and scheme of Article 3(1) of that directive that that provision imposes on the Member States an obligation to achieve a specific, clear and unequivocal result consisting of ensuring that any agglomeration covered by it is equipped with a collecting system enabling all the urban waste water it generates to be collected (judgments of 6 November 2014, Commission v Belgium, C‑395/13, EU:C:2014:2347, paragraph 31, and of 5 March 2020, Commission v Cyprus (Collection and treatment of urban waste water), C‑248/19, EU:C:2020:171, paragraph 27).

25

Next, it is only by way of derogation from that obligation that it is permissible to have recourse to individual urban waste water collection systems (see, to that effect, judgment of 6 November 2014, Commission v Belgium, C‑395/13, EU:C:2014:2347, paragraph 36).

26

Finally, it is apparent from the third subparagraph of Article 3(1) of Directive 91/271 that the use of such self-management solutions, in a given agglomeration, is possible only if two cumulative requirements are met. First, the Member State concerned must establish that it is not justified to install a collecting system in that agglomeration for environmental or financial reasons. Second, where that prior requirement is met, it is also for the Commission to demonstrate that the individual systems for collecting urban waste water or the other appropriate systems which are used in place of such a collecting system ensure protection of the environment equivalent to that achieved by that system (see, to that effect, judgment of 31 May 2018, Commission v Italy, C‑251/17, EU:C:2018:358, paragraph 37).

27

In the present case, it must be stated, first, that Hungary does not dispute that individual urban waste water collection systems are used repeatedly and to a significant extent in the agglomerations concerned by the first complaint. Accordingly, that situation must be considered to be established.

28

Second, that Member State neither maintains nor establishes that that situation is explained, for each of the agglomerations concerned, by the fact that the use of collecting systems for urban waste water is not justified for environmental or financial reasons. It merely claims, in essence, that the self-management systems for the collection of that water which are used in the place of those collecting systems are subject to legal and technical conditions for installation and operation which permit the inference that their use is justified. However, by arguing in this way Hungary does not put forward any environmental or financial reasons demonstrating that the use of collecting systems is not justified.

29

It follows that the first part of the first complaint must be upheld.

30

As regards the second part of the first complaint, alleging infringement of Article 10 of Directive 91/271, it should be noted that that article requires Member States to ensure that urban waste water treatment plants built to meet the requirements of Articles 4 to 7 of that directive are designed, constructed, operated and maintained to ensure sufficient performance under all normal local climatic conditions.

31

As is apparent from the wording of Article 10, the obligation which it imposes on the Member States as regards treatment plants supplements the obligations incumbent on them, under Articles 4 to 7 of Directive 91/271, in relation to urban waste water treatment. Treatment plants, which Article 10 of that directive requires the Member States to equip themselves with, must therefore be designed, constructed, operated and maintained in such a way as to comply with the requirements applicable to the treatment of those waters under Articles 4 to 7 of that directive, from the time when they entered the collecting systems to be installed pursuant to Article 3 of that directive.

32

In that regard, the Court has held, on several occasions, that the obligation imposed on Member States by Article 10 of Directive 91/271 as regards urban waste water treatment plants presupposes that the requirements laid down in Articles 4 to 7 of that directive concerning the treatment of that water have been met, with the result that that obligation cannot be regarded as having been fulfilled where those prior requirements are not satisfied (judgments of 19 July 2012, Commission v Italy, C‑565/10, EU:C:2012:476, paragraphs 41 to 44, and of 6 October 2021, Commission v Italy(System for collecting and treating urban waste water), C‑668/19, EU:C:2021:815, paragraph 94).

33

Similarly, in view of the link between the provisions of Articles 4 to 7 of Directive 91/271 and Article 3 of that directive, the Court has held that those provisions must be regarded as not having been complied with where the obligation consisting of ensuring, beforehand, that any agglomeration covered by Article 3 is provided with a collecting system allowing for the collection of all the urban waste water which that agglomeration generates (see, to that effect, as regards Article 4 of that directive, judgments of 25 October 2007, Commission v Greece, C‑440/06, EU:C:2007:642, paragraph 25, and of 4 May 2017, Commission v United Kingdom, C‑502/15, EU:C:2017:334, paragraph 46, and, as regards Article 5 of that directive, judgment of 28 March 2019, Commission v Ireland(System for collecting and treating waste water), C‑427/17, EU:C:2019:269, paragraphs 166 and 184).

34

Consistently, it must be held that, in the absence of collecting systems for urban waste water as provided for in Article 3 of Directive 91/271, urban waste water treatment plants cannot, contrary to the requirements of Article 10 of that directive, be considered to be designed, constructed, operated and maintained in such a way as to satisfy the requirements laid down in Articles 4 to 7 of that directive.

35

Thus, in view of the link between all those articles, the infringement of Article 3(1) of Directive 91/271 leads to the infringement of Article 10 of that directive.

36

In the present case, since, as is apparent from paragraphs 23 to 29 above, Hungary has failed to fulfil the obligation laid down in Article 3(1) of Directive 91/271, it must be concluded that that Member State has also failed to fulfil the obligation laid down in Article 10 of that directive.

37

It follows that the second part of the first complaint is also well founded and, accordingly, that the first complaint must be upheld in its entirety.

38

Unlike the first complaint, which concerns the issue of collecting urban waste water in the agglomerations concerned by the present action, the second and third complaints both concern the question of the treatment of those waters in the same agglomerations and must therefore be examined together.

39

In the second complaint, the Commission claims that Hungary has failed to comply with the requirements laid down in Article 4(1) of Directive 91/271 as regards the agglomerations of Békés, of Dabas, of Dunavarsány, of Hódmezővásárhely, of Keszthely, of Kéthely, of Kiskunhalas, of Köröm, of Marcali, of Mezőtúr, of Nagykőrös, of Pilisvörösvár, of Soltvadkert, of Szécsény, of Szentendre, of Szentes, of Szigetszentmiklós, of Tököl, of Tolna, of Veresegyház, of Zalaegerszeg and of Zalakaros.

40

In that regard, it notes, first of all, that that provision requires Member States to ensure that urban waste water entering collecting systems is subject to secondary treatment or an equivalent treatment before discharge.

41

Next, it considers that compliance with that obligation means that the collecting systems with which all agglomerations must be provided ensure, fully and effectively, that urban waste water is subject to secondary or equivalent treatment.

42

Lastly, it submits, in essence, that, in the present case, since the agglomerations concerned are not provided with collecting systems complying with the requirements laid down in Article 3(1) of Directive 91/271, those systems must therefore be regarded, as a result, as not complying with the requirements laid down, respectively, in Article 4(1) and Article 10 of that directive.

43

In the third complaint, the Commission submits that Hungary has failed to comply with the stricter requirements applicable to agglomerations located in sensitive areas under Article 5(2) of Directive 91/271 as regards the agglomerations of Keszthely, of Kéthely, of Marcali, of Zalaegerszeg and of Zalakaros. The arguments which it puts forward in support of that position are essentially similar to those underlying the second complaint. However, the Commission submits, in addition, that the provision of which it alleges an infringement, is applicable to the agglomerations in question. Hungary cannot rely on the derogation provided for in Article 5(4) of Directive 91/271, since it has not shown that it complied with the requirements laid down for that purpose. Furthermore, that derogation may be relied on only in so far as Article 3 of that directive has been complied with beforehand.

44

Hungary considers, first of all, that, in so far as the first complaint relied on by the Commission is unfounded, the same can be said for the second complaint.

45

Next, and in any event, even if it were accepted that some of the urban waste water generated by the agglomerations concerned is not collected by a collecting system, that part is nevertheless transported from the individual systems collecting it to treatment plants where it is treated in accordance with the requirements laid down in Article 4(1) of Directive 91/271.

46

Lastly, the third complaint must be rejected on the ground that Hungary decided to make use of the derogation provided for in Article 5(4) of Directive 91/271, that that decision did not meet with opposition from the Commission and that all the requirements necessary to be able to rely on that derogation are satisfied.

47

It should be noted, in the first place, that Article 4(1) of Directive 91/271 provides that Member States must ensure that urban waste water entering collecting systems is subject to secondary treatment or an equivalent treatment before discharge.

48

For its part, Article 5(2) of that directive states that Member States must ensure that urban waste water entering collecting systems is subject, in sensitive areas, to more stringent treatment than that prescribed in Article 4(1) of that directive.

49

As is apparent from the case-law of the Court, those provisions impose on Member States the obligation to ensure that all urban waste water entering collecting systems is subject to secondary treatment or an equivalent treatment (see, to that effect, judgment of 7 May 2009, Commission v Portugal, C‑530/07, EU:C:2009:292, paragraphs 53 and 56) and, in sensitive areas, more stringent treatment than that secondary treatment or equivalent (see, to that effect, judgment of 6 October 2021, Commission v Italy(System for collecting and treating urban waste water), C‑668/19, EU:C:2021:815, paragraph 63).

50

Furthermore, in view of the link which, as stated in paragraph 33 above, unites those provisions to Article 3 of Directive 91/271, they must be regarded as not being complied with where the obligation as to the result to be achieved which that article imposes beforehand on the Member States, as regards the installation of urban waste water collection systems, is not complied with.

51

It follows that, in the present case, since Hungary does not comply with the obligation laid down in Article 3(1) of Directive 91/271 as regards the agglomerations covered by the present action, it must be regarded as not complying, a fortiori, with the obligations laid down in Article 4(1) and Article 5(2) of that directive respectively.

52

In the second place, although it is true that Article 5(4) of Directive 91/271 provides that the conditions required of a treatment plant under, inter alia, paragraph 2 of that article do not necessarily apply to sensitive areas, if it can be proved that certain conditions laid down in paragraph 4 of that article are met, it must be held, in the present case, that Hungary merely claims that those conditions are satisfied and does not demonstrate, by means of specific, precise and comprehensive evidence, how specifically and effectively those conditions were satisfied in good time for each of the sensitive areas concerned by the present action.

53

As regards, in the third and last place, Article 10 of Directive 91/271, it must be borne in mind that, in view of the link which, as stated in paragraphs 31 and 32 above, unites that Article 10 to Articles 4 to 7 of that directive, the obligation which it imposes on the Member States as regards urban waste water treatment plants must be regarded as not having been complied with where the requirements which Articles 4 to 7 of that directive impose beforehand on Member States concerning the treatment of that water are not complied with.

54

In the light of the findings made in paragraphs 36 and 51 above, it follows, in the present case, that Hungary must be regarded as not complying with that obligation.

55

It follows that the second and third complaints must be upheld.

56

The Commission states that it concluded, in its reasoned opinion, that Hungary had failed to fulfil its obligations under Article 15 of Directive 91/271 by failing to demonstrate, by means of up-to-date data complying with the requirements referred to in that article, that it had fulfilled its obligation to monitor discharges from treatment plants which supply the agglomerations covered by the present action.

57

Hungary, for its part, maintains that it complied with those obligations.

58

In accordance with Article 21 of the Statute of the Court of Justice of the European Union and Article 120(c) of the Rules of Procedure of the Court of Justice, every application must contain, inter alia, a summary of the pleas in law submitted. It follows that any application made by the Commission under Article 258 TFEU must not only indicate the specific complaints on which the Court is called upon to rule, but also contain, in a sufficiently clear and precise manner, the essential points of law and of fact on which each of those complaints is based, the failure to comply with those requirements entailing, as the case may be, the inadmissibility of that application or the complaint concerned (see, to that effect, judgment of 10 December 2009, Commission v United Kingdom, C‑390/07, EU:C:2009:765, paragraph 339 and the case-law cited).

59

In the present case, it must be stated that, as regards the present complaint, the Commission does not put forward any legal or factual arguments capable of meeting those requirements, but limits itself, in essence, to referring to the findings and assessments which appear in the reasoned opinion.

60

Accordingly, the fourth complaint must be rejected as inadmissible.

61

Having regard to all the foregoing considerations, it must be declared that:

62

Under Article 138(3) of the Rules of Procedure, the parties are to bear their own costs where each party succeeds on some and fails on other heads. However, if it appears justified in the circumstances of the case, the Court may order one party, in addition to bearing its own costs, to pay a proportion of the other party’s costs.

63

In the present case, since Hungary has essentially been unsuccessful, it must pay three quarters of the Commission’s costs in addition to its own costs. The Commission is to bear one quarter of its own costs.

On those grounds, the Court (Seventh Chamber) hereby: