A green drive in Tianjin will see roughly one-fourth of the city designated as protected area.
A submission to establish the area, which will encompass water sources, wetlands and urban green belts, was approved last week by the Standing Committee of the Tianjin Municipal People's Congress, the city's legislature.
No buildings will be permitted in 60 percent of the area while any construction in the remaining 40 percent must be approved by the city government.
The move by the port city, a major industrial center, will see nearly 3,000 square kilometers fall under the protected area.
Mayor Huang Xingguo said the city's pollution must be dealt with by decisive measures.
"Whoever you are, you cannot live comfortably without a good environment," Huang said as he urged lawmakers to approve the proposal.
Gao Shaolin, a senior legislator in Tianjin, approved the city government's efforts to protect the environment, saying it is the "right approach".
While many cities, he said, have various antipollution plans, some of them might be outside a legal framework.
Ma Jun, a Beijing-based lawyer who specializes in environmental issues, said what Tianjin has done shows determination.
"Compared with an administrative order, which can depend on who is in charge at a particular time, the decision passed by local congress has the same force as a law. It may even harm local economic growth - still an important index to gauge government performance," he said.
Ma expressed concern, however, over the 40 percent area of land that could be built on with special approval.
"Such obscurity can open the back door for law breakers," he said.
Tianjin's "green rate" of non-built-up areas lags behind most cities. Its green areas are 35 percent of the total municipal area, while Beijing's are almost 45 percent.
Zhang Min in Tianjin contributed to this story.
zhaoyinan@chinadaily.com.cn