Every night north-east of the city, between the towns of Nola, Acerra and Marigliano, hundreds of small fires burn in fields and waste ground in what is known as the “Triangle of Death” – which gained its name for the high cancer rates thought to be caused by pollution from the waste.

Camorra gangs are thought to be to blame as they make millions of euros a year by disposing of waste, as well as dumping poisons.

The troops announcement by the Interior Minister, Angelino Alfano, stems from a decree in February designed to fight environmental crime committed by mafia groups, as well as industrial pollution at the ILVA steel plant in the city of Taranto. The decree will allow the deployment of up to 850 military troops in the Triangle of Death.

“The military is staying as long as it’s needed,” Mr Alfano told a meeting of the National Public Safety and Order Committee, which he chaired in Naples on Monday.

He said the three aims of sending in troops were to “punish those responsible… reclaim the lands to avoid the risk of further mafia activity… and prevent the paradox of those areas that have already been reclaimed from being used again for illegal dumping”.

There is already strong evidence that this dumping and illegal burning is to blame for increased rates of cancer and birth defects in the area.

In 2012 a group of US and Italian scientists, led by Dr Antonio Giordano of the Sbarro Institute for Cancer Research at Temple University, in Philadelphia, found that “30 years of Camorra [Neapolitan mafia] and improperly disposed toxic refuse in the zones of northern Naples and southern Caserta” were to blame for rates of breast cancer that were on average 47 per cent above the national norm. Another study found birth defects in the area were 80 per cent above the national average.

The past few months have also seen a surge in murders as the 90 or so clans and their 4,000 affiliates fight turf wars over the lucrative “Ecomafia” business – the illegal disposal of toxic waste. Mr Alfano referred to the series of “brutal Camorra murders” that have occurred since the start of February, adding that investigations were “on the right path”.

The Italian authorities have a history of sending in the troops to the south of the country after flares in mafia activity. But Massimiliano Manfredi, a Naples-born MP for the Democratic Party and a member of the parliamentary Anti-Mafia Commission, said that rooting out the corrupt officials who helped the mafia was more effective then sending in the troops. “You don’t just fight the Camorra with the army. Its real strength stems from the fact that it’s embedded in the public administration,” he told The Independent. “Rather than the military, we need strong controls on public procurement and to insist on the renewal of the ruling class to break the continuity between political power and organised crime. So we need a show of strength, but also to clean out politics where it’s contaminated.”