With the majority of Shanghai's parks now open around the clock, the city has introduced measures to curb potential light pollution.

Currently, 862 parks, representing more than 80 percent of all parks in the city, operate 24 hours a day. While continuous night lighting ensures accessibility and safety, uncontrolled artificial light can lead to light pollution.

The Shanghai Landscaping and City Appearance Administrative Bureau is promoting the development of demonstration parks featuring light pollution control and healthy lighting, with Xujiahui Park serving as the first example.

Fifteen UFO-shaped streetlights have been installed in the park, directing light downward at a fixed angle instead of scattering it in all directions.

Their intensity and color temperature are programmed to adjust according to the time of day and season. The lights shine brightest at 6 pm, when they are turned on, and again just before 6 am, when they are turned off. Between 9 pm and 3 am, they operate at their dimmest, at just 45 to 51 percent of maximum brightness, based on a survey of park visitor habits.

The survey showed that 83.58 percent of visitors arrive between 6 pm and midnight, with numbers dropping significantly after 8 pm.

Maintaining full lighting throughout the night would not only waste electricity but also disturb plants and wildlife, said Tang Wansong, an official with the Xuhui District Light Advertising Administration Office.

Color temperature changes follow the same pattern. It starts at a neutral 4000K white at 6 pm, gradually shifting to a warm yellow below 3300K as the night deepens, creating a calming atmosphere. Before dawn, it rises from 2700K to 5000-6000K, producing a cooler, bluish hue to better match the environment.

The park also features 16 mist-and-light poles equipped with music radar sensors, installed on tall trees along both sides of the pedestrian bridge.

When visitors pass, these "pole performers" project light onto mist sprayed from behind, creating a dreamlike "night sky".

Lighting styles change with the seasons. This summer, the "Firefly Forest" mode immerses pedestrians in a blue-purple mist dotted with "floating" lights, accompanied by the sounds of summer insects.

Along the jogging track, patterned lights project playful images, such as a cartoon white cat peeking from an orange circle with the words "Life is bright, everything is lovely" in Chinese.

"We hope these patterned lights will bring surprise and joy to night runners," said Jin Qiying, deputy chief designer at Shanghai Ruiyi Environmental Design, which was responsible for the park's lighting design.

Jin added that the public will be invited to submit creative designs and texts for the lights in the future.

From "light" to "healthy light", the lighting upgrade at Xujiahui Park is set to be rolled out to other parts of the city, said Tang.

Source: Jiefang Daily