Violence flared as the people of Naples tried to stop police re-opening a landfill site to cope with the mountains of rubbish that have piled up over recent weeks.
Waste collection ground to a halt before Christmas and there are thought to be more than 100,000 tonnes of garbage on the streets.
The government has held an emergency meeting.
The army has shifted mountains of rubbish from schools, but most of them remain shut, along with many universities, on health grounds.
One mother said she had decided not to send her sons to school because the streets were poisonous.
The situation has dogged Naples for years. Officials have thrown two billion euros at the problem and six “trash czars” have been appointed, but a combination of political incompetence, corruption and organised crime has scuppered any solution.
With nowhere to put their rubbish, people have been forced to dump it on the side of the road.