The “Venice bans cruise ships” headline might be one you’ve seen before. Venice already announced a ban on cruise ships from entering Venice’s historic center last April, as we reported.

However, that wasn’t the whole story. That became clear last month when, to the shock of many, massive cruise ships returned to Venice. As Matador then explained, the wording of the original ban said it would take effect only when an alternative docking area for the cruise ships was presented. Since no alternative currently exists, the ships were still permitted to enter the Venetian Lagoon — an already threatened and fragile ecosystem.

Two weeks after the mega cruisers returned to Venice, UNESCO shook things up. The UN agency on cultural heritage said it would put the Venice Lagoon on the endangered list if cruise ships weren’t banned — finally spurring the Italian government into action.

As of August 1, all ships weighing over 25,000 tons will be prohibited from entering the shallow Giudecca Canal that flows past Piazza San Marco. Only small passenger ferries and goods vessels will be allowed to use the canal.

The banning of cruise ships in Venice has always been a controversial issue. Residents have long advocated for the government to ban large ships from the lagoon, due to their pollution, ill effects on the ecosystem, and even accidents that have injured tourists. Tourist operators, local businesses, and the roughly 6000 port workers and their families, profit from the influx of tourists and have argued in favor of the cruise industry.

Whatever your stance on the issue, the ban proves that persistent environmental advocacy and protests can meaningfully impact policy.