The Italian capital's bid is facing an uncertain future with the city's new Mayor Virginia Raggi so far refusing to back it. 

In a letter sent to the Italian National Olympic Committee (CONI) and to Rome 2024, and published by the Italian daily La Repubblica, Greenpeace, the World Wide Fund for Nature, Lipu, Italia Nostra and Legambiente have endorsed the bid’s proposal for Rome.

"The Olympics can be an opportunity for recovering abandoned areas and buildings, coexisting with and developing the city rather than exploiting it," said Marco Parini, President of Italia Nostra, to La Repubblica. 

Italia Nostra supports the bid’s “priorities for recovering existing structures” and for providing accessibility to all structures through comprehensive public transportation that combines a rail system and bike paths, and its vision to develop and promote the Tiber River and the cultural landmarks of Rome. 

The choice of the Tor Vergata area for the location of the Olympic Village has also received the green light since it "aims to restore the abandoned Vele di Calatrava structures, brings the subway to an area of Rome that has a great need for it, and plans to use existing University student dormitories and hospital facilities."

The document includes important input regarding existing and new infrastructure that is going to be studied by Roma 2024 experts, it is claimed.

"We are very pleased to receive the endorsement by top environmental organizations," said Luca Di Montezemolo, President of Roma2024.  

"We view environmental organisations as indispensable partners for our effort to achieve a sustainable Olympic bid and I personally value their feedback."

Following a meeting with Pope Francis last week, Raggi had claimed the Rome 2024 bid "isn't ethical" and warned she was not prepared to subject its citizens to "more debt for at least 20, 30 or 40 years".

During the election, Raggi campaigned on a manifesto of trying to sort out Rome's most pressing problems, including traffic congestion, waste management, lack of social housing and the endemic corruption in the city.

Giovanni Malagò, the President of CONI, is hoping the letter will help persuade Raggi to support their campaign. 

"Rome’s Olympic and Paralympic Games will set a new standard in terms of both addressing the needs of the Host City and serving the athletes before, during and after the Games," he said. 

"The citizens of Rome demand a city with an efficient, environmentally friendly, public infrastructure, that is accessible to all."

Rome is facing opposition from Budapest, Los Angeles and Paris.

The International Olympic Committee is due to choose the host city at its Session in Lima in September 2017.