During the nomination process, he said there had been a noticeable shift in attitude toward conservation policy.

In May 2017, China promulgated its first regulation on coastlines, requiring that at least 35 percent of the total coastline should remain undeveloped until 2020.

In July 2018, the State Oceanic Administration stopped approving reclamation projects, except for those passed by the central government aimed at infrastructure construction, public services and national defense, for the rest of that year.

Against this backdrop, Yancheng announced that the Tiaozini Wetland Park, occupying 12,746 hectares, would be built and that the entire Tiaozini area would be added to the World Heritage Site nomination.

As a result, the Phase I heritage site covers 186,400 hectares, taking in Dongtai, Sheyang county and Dafeng and Tinghu districts.

Yuan, from the Yangcheng development and reform commission, said placing Tiaozini under preservation means it can no longer use encroaching land for economic development.

Land in Yancheng near the Yangtze and Yellow river estuaries, rich in sediment from the two rivers and which took up 582 kilometers of coastline, had continued to encroach toward the Yellow Sea.

This area had expanded by 2,000 to 3,333 hectares a year, Yuan said. But now, as the upstream sections of the rivers have become much cleaner, this encroachment has fallen to about 500 hectares.

"We got the land for nothing," Yuan said. "It had long been considered for economic development. Now, it will become a habitat for birds."

Yu Quansheng, deputy director of Yancheng's nature resources and planning bureau, said many development projects within the heritage site will gradually be ended.

Fishing ponds or farmland rented to individuals or private companies-often by governments at all levels-have to be bought by the authorities even though the leases are not due to expire, including a 533-hectare reservoir in Tinghu district.

"The rent for 1 hectare of water is usually more than 15,000 yuan ($2,156) a year," Yu said. "Some 600 million to 700 million yuan will be needed to buy land in Dafeng and Sheyang. This has become a budgetary burden."

In addition, he said court action has been taken in some cases to obtain land.