Italy has fined Ryanair 3 million euros for failing to help passengers after cancelling their flights during the volcanic ash crisis.
Italy's civil aviation authority ENAC said it knew of 178 cases of passengers who did not receive mandatory assistance, such as food, between 17 - 22 April.
Ash from the Eyjafjallajokull volcano in Iceland triggered a shutdown of European airspace last month. An estimated eight million tourists and business travellers were stranded.
ENAC accused Ryanair of failing to provide passengers at Ciampino airport in Rome with drinks, foods and accommodation as required by European law.
It said most other airlines managed to meet their obligations despite the difficult circumstances.
Ryanair denies the accusation.
Under EU Regulation 261, if a flight is cancelled, those flying with European carriers into or out of the EU have the right to a refund or to be re-routed.
If passengers chose the latter, they have the right to care - such as accommodation and meals - while they wait.