Toilet doors turn clear when smoke detected in China mall

A shopping center in Shenzhen is exposing bathroom smokers by turning toilet doors transparent. The system is live at Shuibei International Center in the Luohu District. Signs inside the men’s restroom warn, “Smoking makes the glass transparent.” A spokesperson said fines and temporary bans failed to stop indoor smoking. The doors include a glass window with a silver halide compound. Sensors detect cigarette smoke and heat, triggering molecules to switch from frosted to clear. When triggered, a loud message fills the restroom. “In accordance with the Secondhand Smoke Prevention Ordinance, this is a public place where smoking is prohibited.” The stunt went viral on Chinese social media. One commenter wrote, “Smoking in men’s restrooms in China is practically ubiquitous.” Others questioned privacy and possible malfunctions. The doors are currently in a trial period. If backlash stays limited, the mall plans to keep them, betting public embarrassment beats another fine.