Illuminating argument
Dai Jianfeng, who has photographed night skies across China, has followed dark sky conservation efforts in Shenzhen.
Xichong, a coastal community, lies on the outskirts of Shenzhen, which has more than 18 million residents. Known for its beaches and the Shenzhen Astronomical Observatory, Xichong draws visitors for both seaside recreation and stargazing.
"Xichong and Ngari represent two extremes," Dai said. "Ngari is very remote, but there are also places close to our cities where people can still see the stars, and those places can be protected."
In 2023, Xichong became China's first International Dark Sky Community, certified by the US-based nonprofit DarkSky International. The designation recognizes commitments to managing outdoor lighting and raising public awareness of dark sky conservation.
Dai said while the illuminated skyline around Shenzhen Bay is part of the city's urban identity, places such as its mangrove habitats and Xichong have different environmental needs.
That distinction is reflected in Xichong's lighting rules.
A local regulation introduced in 2024 sets limits on brightness, color temperature, direction and operating hours, aiming to keep roads and public spaces usable without allowing unnecessary light to spill into the sky.
The results can be measured.
On clear, moonless nights, Xichong's recorded sky brightness improved from 18.5 magnitudes per square arcsecond (MPSAS) in 2022 to 19.7 in 2025, according to the Shenzhen municipal government. A higher reading indicates a darker sky.
Jiang Benyan, a researcher at Guangzhou University who studies light pollution and urban planning, sees value in making dark skies accessible to people living in densely populated cities.
"Large cities have dense populations, and more people need opportunities to experience darkness and see the stars," Jiang said. "Establishing dark sky conservation areas near cities is especially important for public education and spreading awareness of their value."
Her research has identified relatively dark areas on the outskirts of Guangdong's capital, Guangzhou, particularly around Conghua and Zengcheng districts.
At the summit of Apoliu Mountain, near Nankun Mountain National Forest Park, the best recorded sky brightness was 21 MPSAS, with the Milky Way able to be seen with the naked eye.
But the mountain is not isolated from surrounding development. Lighting from an expressway, commercial facilities 6 km away, and neighboring towns already affect the nighttime environment. Jiang warned that further tourism development in the area could threaten the existing level of darkness.
The implications extend beyond stargazing. Artificial lighting can disrupt the natural day-night cycles that guide wildlife migration, feeding and reproduction, she said. In an analysis of more than 400 protected natural areas in the Pearl River Delta, Jiang's team found that they were sensitive to artificial lighting within 6 to 8 km.
"Dark sky protection can evolve from a conservation area effort into a matter of community and urban governance," she said.
