Some shopping malls in Shenzhen, China, have begun installing toilet cubicle doors made from so-called “smart glass”, a move that has quickly gone viral on Chinese social media and overseas platforms. The technology is designed to deter people from smoking inside indoor public toilets, a problem mall operators say has persisted despite repeated warnings and enforcement efforts.
Under normal conditions, the glass doors appear frosted and opaque, providing users with full visual privacy. However, the system is linked to smoke sensors installed within the toilet cubicles. If cigarette smoke is detected, the glass can automatically switch from opaque to transparent within seconds. In some cases, an audible alarm may also be triggered at the same time.
According to reports circulating online, the primary objective of the system is deterrence. By making the smoker instantly visible to others outside the cubicle, mall operators hope to discourage repeat offenders who continue to flout indoor smoking bans. Complaints about cigarette smoke lingering in enclosed toilet areas, particularly in high-traffic malls, have reportedly driven management to explore stronger measures.
Videos and photos of the transparent doors activating have since spread rapidly online, drawing a mix of amusement, shock and criticism. Many netizens expressed disbelief that such a method was even considered, while others joked that it was an “effective but ruthless” solution to a long-standing issue.
How The Smart Glass System Works
Smart glass technology, sometimes referred to as switchable glass, uses electrical currents to change the opacity of the glass. When powered, the glass becomes transparent; when switched off, it returns to a frosted or opaque state. In the Shenzhen malls, this mechanism is reportedly automated and linked directly to smoke detection devices installed within each cubicle.
Once smoke particles are detected, the system responds almost immediately, leaving little time for the person inside to react. This rapid response is what has made the concept so controversial, as it can expose the individual in a highly private setting with no manual override.
Mall operators cited in Chinese media reports have said the measure was introduced after more conventional approaches failed. These included no-smoking signs, routine cleaning, and patrols by security staff. Despite China’s regulations against smoking in indoor public places, enforcement remains uneven, especially in semi-enclosed areas like toilets.
The malls involved have reportedly placed notices outside restrooms warning users about the smart glass feature. However, critics argue that warning signs alone do not fully address concerns about dignity and personal rights.
Privacy Concerns And Public Reaction
Unsurprisingly, the installation of transparent toilet doors has triggered heated debate around privacy and proportionality. Many online commentators questioned whether exposing someone mid-use, even if they are violating smoking rules, crosses an ethical line.
Some legal experts in China have suggested that while the intention may be to enforce public health rules, the method could potentially violate personal privacy protections. Toilets are widely regarded as spaces where individuals are entitled to a reasonable expectation of privacy, regardless of misconduct.
Others, however, defended the move, arguing that smokers who ignore repeated warnings are inconveniencing everyone else. Passive smoking in enclosed toilet spaces poses health risks, particularly to children and the elderly, and cleaning staff are often the ones most affected by lingering smoke.
As the discussion continues, it remains unclear whether the smart glass system will be rolled out more widely or scaled back in response to backlash. For now, the Shenzhen toilets have become a striking example of how technology is increasingly being used to enforce public behaviour — even in the most private of spaces.
Whether such measures would ever be considered acceptable in places like Singapore, where privacy norms and enforcement standards differ, is another question entirely. What is clear is that the viral attention has reignited broader conversations about how far authorities should go in balancing public health, deterrence and personal dignity.