China has designated 25% of its onshore territory "ecological conservation" areas, limiting development and human activities in order to improve the environment and conserve resources.

The Ministry of Ecology and Environment was tasked with identifying areas in need of protection a decade ago, when the government acknowledged that decades of "irrational development" had put its ecological safety under severe strain.

Cui Shuhong, a director from the ministry's Nature and Ecology Conservation Department, told a news conference on Wednesday that "red lines" had been drawn around zones that served a major ecological function, and areas that were sensitive and vulnerable along with important regions for biodiversity.

"We will delineate and strictly guard the ecological protection red lines...and rein in various violations of the ecological environment that harm the vital interests of the people," Cui said.

In 2017, the central government made clear that local government officials were responsible for protecting designated areas, and later ordered an ongoing crack down on industrial plants, farms, piggeries and even residential houses built within the red lines.