1. The power of the Commission to enforce decisions taken pursuant to Articles 30 and 31 shall be subject to a limitation period of 5 years.

2. Time shall begin to run from the day on which the decision becomes final.

3. The limitation period for the enforcement of penalties shall be interrupted:

(a) by notification of a decision varying the original amount of the fine or periodic penalty payment or refusing an application for variation; or

(b) by any action of the Commission or of a Member State, acting at the request of the Commission, designed to enforce payment of the fine or periodic penalty payment.

4. Each interruption shall start time running afresh.

5. The limitation period for the enforcement of penalties shall be suspended for so long as:

(a) time to pay is allowed; or

(b) enforcement of payment is suspended pursuant to a decision of the Court of Justice or to a decision by a national court.