Miljönämnden i Helsingborgs Kommun (the Environmental Committee in Helsingborg Municipality / the Committee) decided on 28 September 2000 that the shipping companies Scandlines AB, Scandlines Danmark A/S, Scandlines Öresund I/S, Helsingborg-Helsingör Färjorna AB - now HH-Ferries AB (HH), and Sundbusserne A/S (S) had to ensure that all main and auxiliary engines on their ferries within the Helsingborg Port area were equipped with selective catalytic exhaust purification. The injunctions were accompanied by fines.

The shipping companies appealed the Committee's decision to the County Administrative Board of Skåne County, which on 13 September 2002 upheld the appeals and revoked the Committee's decision. The Committee appealed to the Environmental Court, which in the judgment now being appealed, rejected the Committee's appeal. The Committee withdrew its action against the Scandlines companies. The Committee requested that the Environmental Court of Appeal annul the Environmental Court's judgment and the County Administrative Board's decisions, and uphold the Committee's injunction to the extent that it was directed against HH and S, with amendments.

Held: Appeal upheld. The judgments below are annulled. This Court orders as follows:

• HH shall ensure that all main and auxiliary engines on its ferries within the Helsingborg Port area are equipped with selective catalytic exhaust gas purification by 31 December 2006.
• S shall ensure that all main and auxiliary engines on its ferries within the Helsingborg Port area are equipped with selective catalytic exhaust gas purification by 1 June 2007.
• The injunction does not apply to extra vessels which - after the approval of the Committee in each particular case - are temporarily deployed during the high season, or when ordinary vessels are temporarily taken out of service due to overhaul, breakdown or similar reasons.
• For S, the injunction is combined with a fine of SEK 500,000 for each vessel where the injunction is not complied with within the prescribed time.

The shipping companies have questioned the Committee's competence as a supervisory authority. It is therefore important for future supervisory work that this Court clarifies what the Committee may, and may not, do with regard to shipping. Future regulatory issues are not limited to emissions of nitrogen oxides, but other risks to human health and the environment may arise. If the legal situation is not clarified by this Court, each supervisory case will be problematic.

In support of its action, the Committee relied on a legal opinion by Professor Jonas Ebbesson to the effect that the Committee's measures are not contrary to Sweden's international obligations; that Sweden as a port State can formulate national environmental protection requirements regarding air quality that go beyond MARPOL 1973/78; and that the way in which the protection requirements were communicated was not contrary to the UN Convention on the Law of the Sea (UNCLOS):

A State's right to deny or condition foreign ships' access to certain ports follows from international customary law, which becomes applicable unless otherwise provided by international agreements. The international regulation of pollution from ships is primarily found in MARPOL and UNCLOS. In addition, there are a number of regional Conventions relating to such pollution, such as the Baltic Sea Convention 1992.

Both MARPOL and UNCLOS impose on the flag State the primary responsibility for exercising control over and, in the event of infringements, prosecuting vessels flying its flag, but the flag State has no exclusive jurisdiction over vessels located in or near the territories of other States. Other States can thus, in their capacity as coastal or port States, prescribe and enforce environmental protection rules against these ships. A coastal State is the State within whose coastal waters a foreign vessel sails. A port State is the state in which a foreign ship voluntarily enters port.

The environmental protection requirements defined by MARPOL are both minimum limits for flag States and maximum limits for coastal States in relation to ships under their jurisdiction. On the other hand, MARPOL's protection rules do not imply a maximum limit for port States in relation to foreign vessels. When MARPOL was adopted in 1973, negotiations on UNCLOS were ongoing. Article 9.2 of MARPOL therefore states that the Convention was not intended to prevent legal developments under UNCLOS, or States' views on coastal and port State jurisdiction. MARPOL must therefore be seen in the light of UNCLOS, and in particular art 211.3, which regulates the port State's ability to set additional environmental protection requirements. This also applies to MARPOL's certification provisions, which aim to facilitate and make uniform verification of compliance with the requirements of MARPOL (and other IMO Conventions). Further control of foreign vessels regarding compliance with international environmental protection requirements should in principle only take place when there are clear reasons for a more in-depth examination. If special national environmental protection rules have been adopted, however, the certificate rules do not prevent the port State from checking their compliance. MARPOL must be interpreted in the light of UNCLOS rules.

Although neither MARPOL nor UNCLOS prevent states from imposing specific national requirements as a condition for ships to call at their ports, this possibility must not be abused. UNCLOS's requirements for urgency must be respected, and national requirements that go beyond MARPOL and UNCLOS must be justified on objective grounds.

In addition, national environmental protection rules must not discriminate against foreign vessels. This principle is formulated in art 227 of UNCLOS. Like other international contexts where discrimination is not permitted, it means a ban on legislation that explicitly makes a difference between ships from different countries (de jure discrimination) and on the authorities applying neutral rules in a discriminatory manner (de facto discrimination).

Furthermore, it is required that foreign vessels be given the opportunity to anticipate what environmental protection and other requirements are placed on them to be allowed to call at a port. Therefore, art 211.3 of UNCLOS provides that States wishing to introduce specific requirements to limit pollution to protect the marine environment must publish these requirements in a proper manner ('give due publicity') and communicate the requirements to the IMO ('competent international organisation'). The statute itself is explicitly limited to measures to protect the marine environment. Given the purpose of UNCLOS - to make it easier for foreign ships to anticipate the national requirements of the port State - and the fact that the issue of air pollution from ships had not been raised in an international context in 1982 (when UNCLOS was adopted), corresponding requirements for publication and reporting should also apply to national protection requirements aimed at improving air quality. However, no obstacle to such requirements is set.

The Committee's measures relate to Sweden's competence as a port State, not a coastal State. In the context of international law, each State decides which authority is to issue regulations, formulate requirements and exercise actual control. If Sweden so wishes, control and regulatory tasks can be delegated to municipalities. In other words, it is a question of Swedish law whether municipalities, county administrative boards, the Swedish Maritime Administration, or another authority should control foreign ships in Swedish ports. There is nothing to suggest that the measures here would be discriminatory. While several articles in UNCLOS refer to national laws and regulations, art 211.3 regulates specific national requirements as a condition for the entry of foreign vessels into their ports. This suggests that the specific requirements may be formulated not only by general norms (law, ordinance, or regulation), but also in the form of targeted injunctions or in other ways. The fact that a new MARPOL Annex on air emissions has been adopted shows that the need to control these pollutants has also gained international recognition. Air pollution measures can therefore not be considered unreasonable in general. The Committee claims that the ferries account for a large part of the nitrogen oxide emissions in the Municipality and that they significantly contribute to the Municipality's difficulty in meeting current environmental quality standards. If this information is correct, the measures imposed cannot be considered unreasonable. According to UNCLOS, the specific environmental protection conditions for ports of call must be duly published and reported to the IMO. Formally, this requirement has not been met. For an assessment of whether the Committee's measures are contrary to art 211.3 of UNCLOS, and whether publication can be considered appropriate, the purpose of the statute should again be taken into account. The reason for publishing special environmental protection conditions is that foreign vessels that may be affected must be able to anticipate the specific requirements before entering the port. In this case, the measures are only aimed at a limited number of ferry companies, all of which continuously operate their ferry services in the port of Helsingborg. The assessment of what is due publication should therefore be made primarily from the perspective of the ferry companies concerned. The measures submitted were notified to the ferry companies well in advance of their completion, so their protection interest has not been infringed in relation to art 211.3 of UNCLOS.

The Swedish Maritime Administration notes that the Port of Helsingborg is a coastal port. The Port is therefore part of Sweden's maritime territory over which Sweden has both legislative and executive jurisdiction. Even when they are in Swedish territory, foreign ships are under the jurisdiction of their respective flag States. This is reflected in art 94 of UNCLOS. However, this rule on the flag State's jurisdiction does not prevent Sweden from exercising its jurisdiction over its own maritime territory:

An important limitation of Sweden's opportunities to exercise its jurisdiction over its maritime territory applies to Sweden's actions as a coastal State, or in other words Sweden's actions towards ships that are on Sweden's territorial sea. A coastal State may, among other things, issue rules for progress on its territorial sea aimed at preserving the coastal State's environment and preventing, limiting and controlling its pollution. The restriction means that such rules may not be applied to foreign ships when dealing with ships' design, construction, or equipment if the rules do not express generally accepted international rules or standards. This is stated in art 21 of UNCLOS. There is no restriction similar to that in art 21 for rules introduced by a port State to protect the air environment. However, art 211.3 of UNCLOS provides that States which impose special requirements for the prevention, limitation, and control of pollution of the marine environment as a condition for foreign vessels to gain access to their ports shall publish such requirements and notify the IMO. Furthermore, measures taken by States to protect and preserve the marine environment may not discriminate against vessels of another State under art 227 of UNCLOS.

However, it is doubtful whether these abovementioned rules (arts 211.3 and 227), contained in Pt XII of UNCLOS, which deal with the protection and conservation of the marine environment, also include rules which the present case concerns, ie rules on protection or restriction of emissions of nitrogen oxides. Where emissions of nitrogen oxides into the air and nitrogen oxides are harmful to the air, or where such emissions lead to acidification which mainly affects the terrestrial environment and freshwater rivers, it is most probable that these provisions do not apply.

This leads to the conclusion that UNCLOS does not prevent a port State from legislating on the protection and limitation of emissions of nitrogen oxides, or from taking legal action against a foreign-flagged vessel to ensure compliance with such legislation. UNCLOS most likely does not lay down conditions for legislation or interventions of this kind either.

The Committee has a responsibility for supervision of health protection within the Municipality, which is not linked to only environmentally hazardous activities. If the vessels thus affect the health situation in the Municipality, the environmental committee may have the authority, on the basis of the Environmental Code's supervisory provisions (Ch 26 s 9) and general rules of consideration (Ch 2), to order protective measures and restrictions. A prerequisite for this is that international law or Swedish legislation outside the Environmental Code does not put obstacles in the way.

The Environmental Court has ruled that international law - UNCLOS and MARPOL 73/78 - does not preclude a coastal State from taking legal action against a foreign vessel if this is necessary to ensure compliance with the coastal State's environmental legislation.

UNCLOS regulates virtually all aspects of the peaceful uses of the oceans and seabed. MARPOL aims to prevent marine pollution from ships. Annex VI to the latter Convention deals with air pollution from ships and entered into force in May 2005 and was thus not in force at the time of the judgment of the Environmental Court. It has now been implemented in Swedish law through the Swedish Maritime Administration's regulations and general guidelines on measures against pollution from ships, SJÖFS 2005: 8. The regulations entered into force on 19 May 2005.

MARPOL's Annex VI and the Swedish Maritime Administration's regulations regulate, among other things, emissions of nitrogen oxides from ship engines. Thus, as a general rule, emissions from diesel engines with a power generation exceeding 130 kW and installed on ships built or substantially rebuilt in 2000 or later may not exceed certain limit values, stated as g/kWh.

This Court finds that the provisions of UNCLOS do not prevent a Swedish authority, as a representative of the port State, from intervening against a foreign ship with a requirement to reduce emissions of nitrogen oxides into the air for the protection of health. According to this Court's assessment, there is also no obstacle under the provisions of MARPOL to impose more far-reaching requirements on ships calling at Swedish ports than the Convention requires, if this is justified under national environmental legislation. This is because the Convention does not express any rule that limits the possibility for port States to set such requirements in relation to foreign ships. However, such requirements must not be discriminatory. In this case, where the requirements are aimed at shipping companies that have extensive regular services to and from the Port of Helsingborg and where the same requirements are set regardless of which flag the ships sail under, the requirements cannot be considered discriminatory. According to this Court's assessment, the injunctions thus do not conflict with Sweden's international obligations.