Every home has one: that pair of shoes that makes its presence known the moment it’s slipped off. The kind that quietly lurks by the door until its unmistakable stench announces itself.
And while most people chalk it up to “sweaty feet” or shrug with embarrassment, two Indian researchers decided smelly shoes were more than just a nuisance, they were a scientific mystery worth solving.
Their curiosity has now earned them a place in the quirky but prestigious world of the Ig Nobel Prize, the annual award that honours “achievements that first make people laugh, then think.”
Vikash Kumar, a 42 year-old assistant professor of design at Shiv Nadar University outside Delhi, and his former student, Sarthak Mittal, 29, took on the challenge after a simple observation: shoe racks across student hostels were essentially biohazard zones. To prove it wasn’t just in their heads, they surveyed 149 university students.
Their findings confirmed what many secretly know: more than half admitted to being embarrassed by the smell of their own or someone else’s shoes. Nearly all stored them in racks, and few had heard of specialised deodorising products.
Instead, home remedies ruled stuffing shoes with tea bags, sprinkling baking soda, or spraying deodorant. But these DIY hacks rarely did more than mask the stench.
The real culprit, Kumar and Mittal noted, wasn’t the shoe itself but what thrived inside it: Kytococcus sedentarius, a bacterium that loves sweaty, enclosed environments. Previous studies had shown this microbe was behind the sharp, cheesy odour that can make removing shoes a social gamble.
So, the researchers turned to ultraviolet light, specifically UVC rays, which are known to kill bacteria. If the bacteria could be eliminated, they reasoned, so could the smell.
For their experiments, they chose the smelliest shoes available: those worn by university athletes. The bacterial build-up, they discovered, was heaviest near the toe box. By blasting that area with UVC light, they could measure exactly how long it took to neutralise the odour.
The results were as fascinating as they were funny. At the start, the shoes were described as having a “strong, pungent, rotten-cheese-like” smell. After just two minutes of UVC exposure, the odour dropped to an “extremely low, mild burnt-rubber smell.” By four minutes, the foul stench had vanished, leaving behind only an “average burnt rubber” scent. Six minutes in, the shoes were odour-free and comfortably cool.
But there was a catch. Too much exposure 10 to 15 minutes overheated the rubber, replacing the victory of freshness with the unmistakable smell of “strong burnt rubber.” In other words, timing was everything.
What began as an everyday annoyance became an unusual scientific quest. The project highlighted how humour, curiosity, and a little ingenuity can turn even smelly shoes into a subject of serious study. And in doing so, Kumar and Mittal have given the world more than a laugh they’ve offered a glimpse of a practical, if unconventional, solution.
For now, the pair’s experiment lives in the realm of research, but it hints at a future where shoe racks could double as sterilisation stations. Imagine slipping off your sneakers and sliding them into a UV-powered rack that zaps bacteria before they ever get the chance to stink.
