VENICE.- To protect its fragile ecosystem and stunning architecture, Venice has taken bold steps. In recent years, it has banned cruise ships from its lagoon and built sea walls to keep out high tides.

Still, the city remains under serious threat, United Nations experts warned this week.

The United Nations’ culture agency, UNESCO, proposed in a document released Monday to include Venice and its lagoon on its World Heritage in Danger list. It said the city had not made enough progress in preventing damage from mass tourism, climate change and development projects, adding that the corrective measures that Italy has proposed “are still insufficient.”

Some prominent Venetians took issue with UNESCO’s critique. Renato Brunetta, a former government minister who now leads a foundation aiming to make Venice the world’s capital of sustainability, said the city was better equipped than most places to face today’s challenges thanks to initiatives including the sea walls and the cruise ships ban.

“Venice has been a more fragile city than the others,” he said. “Paradoxically now it’s the most secure.” He cautioned that the agency’s recommendation to redirect large ships to other ports would damage the city’s livelihood.

The office of Venice’s mayor and Italy’s culture ministry did not immediately respond to requests for comment.

Climate activists said that Venice and Italy should not miss this opportunity to protect the city.

The UNESCO list, which includes 55 endangered sites from the Old City of Jerusalem to Timbuktu, is aimed at spurring conservation, according to the agency. Including a site on the list commits the United Nations to develop a plan of corrective measures alongside national authorities and then monitor the implementation.

UNESCO’s recommendation is not yet final: It will go to a vote next month at the World Heritage Committee, made up of 21 member states, including Italy.

Venice has come close to the endangered list before.

In 2019 UNESCO warned the city about the “damage caused by a steady stream of cruise ships,” and in 2021, the government banned the ships to avoid what it called “the real risk” of the city being listed as World Heritage in Danger.

A new system of sea walls went into operation in 2020 and has already protected Venice from dozens of high tides that flood the city and erode ancient buildings.

Still, UNESCO said this week that the sea wall system was not complete and needed modernization and maintenance. The agency acknowledged that projects were planned or underway to improve the lagoon’s ecosystem, but added that work on measures to mitigate any environmental damage resulting from the sea walls must continue.

Modeling and prevention of the effects of climate change would also be needed as high tides in Venice become more frequent, UNESCO said.

The agency said Italy had not responded to its invitation to collaborate on corrective measures it had previously requested.

It also urged authorities to reduce pollution at the nearby industrial port of Marghera.

In previous years, Venice has deployed technological tools to monitor and control the flow of tourists, and promised a ticketed booking system for visits to the city. That idea has faced strong opposition from many residents and has not yet materialized.

Brunetta, the former minister, recalled that when he was young, he used to help his father sell gondola statuettes near Venice’s railway station. While the city was suffering from an excess of tourism, it also needs tourists to survive, he added.

“Tourism has always been a lifeblood for Venice,” he said.

This article originally appeared in The New York Times.