The announcement is meant to protect the Cabo Pulmo reserve, the only coral reef in the Gulf of California, a formerly over-fished area where marine life has exploded following a decision almost two decades ago by local residents to stop commercial fishing and develop ecotourism activities instead.
But in 2008, federal authorities granted initial permits for a Spanish developer to build about 30,000 hotel rooms, golf courses and a marina on a strip of seaside desert about a 90-minute drive northeast of the Los Cabos resorts. Two years later, in the face of widespread protests, authorities added a series of conditions, including extensive studies of ocean currents, to ensure that sediment, runoff and waste form the planned resort wouldn't harm the reef, parts of it just 30 feet (10 meters) offshore.
Calderon said Friday the permits were being withdrawn because the developer, which ran into financial problems during Europe's financial crisis, hadn't proved the 9,400-acre (3,800-hectare) resort, known as Cabo Cortes, wouldn't harm the environment.
"Because of its size, we have to be absolutely certain that it (the project) wouldn't cause irreversible damage,
Fighting the planned resort became one of the main causes of Mexican environmentalists, who staged protests in which demonstrators paraded with tropical fish cutouts, tossed a giant life-ring into the sea and staged petition drives to stop the project.
Omar Vidal, head of the environmental group WWF Mexico, called Friday's announcement "an important victory, because it shows that when the public organizes, it can achieve great things."
"This sets an important precedent and sends an important message to Mexican and international investors, that this type of tourist development, based on mass scale and golf courses, is no longer acceptable in Mexico," Vidal said.
The developers, whose firm is known as Hansa Baja Investments, said in a press statement that they would rethink the project and re-submit another proposal for approval. Calderon said during his speech Friday they could do so, but should consult scientists, inhabitants and environmentalists in the planning process.
"The company will submit a new project developed with the advice of qualified environmental advisers ... which will be compatible with the conservation and preservation of the area's environment," according to the statement, distributed by a public relations firm.
The project's original developers had included Madrid-based builder Hansa Urbana, which suffered financial setbacks in part because it overextended in building resorts along the Spanish coast.
But the PR firm Llorente and Cuenca said the project was now owned by "several private investors."
In the past, supporters of the project had said most of the resort's land would be left in its natural state.
Calderon said the case showed that "the federal government is sensitive to both the concerns of the inhabitants of the area and the scientific and environmentalist communities, as well as to the needs for legal certainty that any investment requires."
The fight against the resort has lasted for years, with environmentalists suggesting collusion between government regulators and the developers.
Vidal said that "while this is a victory, this is not the time to let our guard down, because there are other similar projects in the pipeline."
Calderon has said he wanted to be remembered as an environmentalist president, and during his term strict rules were enacted against projects that alter coastlines by removing mangrove swamps, though enforcement has been spotty.
Seventeen years ago, Cabo Pulmo's shallow reef was, like many in Mexico, degraded by commercial fishing boats, which often dragged their anchors or nets through the coral, to get at valuable species that lived there.
In 1995, with support from a local university, the government declared the reef a protected area and later upgraded it to marine park status.
The effort was aided by local residents, who largely transformed their economy from fishing to ecotourism, and the amount of life on the reef blossomed. A study by the Scripps Institution of Oceanography in California found that the biomass at the Cabo Pulmo reef—the total weight of living species—rose by 460 percent.
The reef is now so healthy that fish migrate from it to neighboring areas, helping fishermen there.