1. When serious environmental problems exist, the Member State responsible may limit or refuse the exercise of traffic rights, in particular when other modes of transport provide appropriate levels of service. The measure shall be non-discriminatory, shall not distort competition between air carriers, shall not be more restrictive than necessary to relieve the problems, and shall have a limited period of validity, not exceeding three years, after which it shall be reviewed.
2. When a Member State considers that action under paragraph 1 is necessary it shall, at least three months before the entry into force of the action, inform the other Member States and the Commission, providing adequate justification for the action. The action may be implemented unless within one month of receipt of the information a Member State concerned contests the action or the Commission, in accordance with paragraph 3, takes it up for further examination.
3. At the request of another Member State or on its own initiative, the Commission may, in accordance with the procedure referred to in Article 25(2), suspend the measures if they do not meet the requirements of paragraph 1 or are otherwise contrary to Community law.