As cities around the world search for ways to cope with increasingly frequent heatwaves, some residential neighborhoods in China are using an unusual cooling technology.
Videos showing a fine water mist spraying from the rooftops of apartment buildings have gone viral online. The system uses high-pressure nozzles to cool the surrounding air, significantly reducing temperatures and helping combat the urban heat island effect.
The technology is being used in several Chinese cities, including communities in Shanxi Province. Its purpose is not to create artificial rain, but to cool the surrounding area through the evaporation of tiny water droplets, which absorb heat from the air as they fall.
How does the “rooftop rain” system work?
High-pressure nozzles installed on the roofs of residential buildings produce an ultra-fine mist. Because the droplets are extremely small, most of the water evaporates before reaching the ground. This evaporation process absorbs heat from the surrounding air, creating a cooling effect similar to the way perspiration cools the human body.
According to Chinese media reports, the system can lower the temperature of building surfaces and nearby outdoor areas by approximately 5 to 8 degrees Celsius (9 to 14 °F). Besides making outdoor spaces more comfortable, it also reduces heat absorption by rooftops and building facades, decreasing the need for air conditioning indoors.
Viral videos spark global interest
Over the past few days, videos of the so-called “rooftop rain” system have spread rapidly across social media, prompting discussions about the future of urban cooling technologies.
According to media reports, Chinese authorities also confirmed that the footage is authentic after some users speculated that the videos had been generated using artificial intelligence. In addition to lowering temperatures, the water mist is also believed to help reduce air pollution by trapping dust particles and smog.
प्रचंड गर्मी से राहत के लिए सेंट्रल चीन के #Shanxi में मिस्ट कूलिंग सिस्टम का प्रयोग किया जा रहा है।
इससे तामपान 5 से 8 डिग्री कम हो जाता है। pic.twitter.com/jkacrlqmQt— Madhurendra kumar मधुरेन्द्र कुमार (@Madhurendra13) July 1, 2026