If you’ve been clutching your chest every time a kanwar yatra truck passes by, you’re not alone. Towering speaker rigs strapped to trolleys, flags snapping above them, lead the procession into Delhi-NCR. This year, as Kanwar Yatra peaks across the capital and western Uttar Pradesh, the conversation isn’t only about traffic. It’s about what happens to a city’s ears when devotion arrives at concert volume, night after night, for close to three weeks. (Credit: PTI)

Rules have capped sound systems at 55 decibels between 6 am and 10 pm, dropping to 45 decibels overnight — close to the level of a quiet office. In practice, sound from Kanwar DJ trucks often runs far higher, into the 100-decibel range typical of large speaker systems at full volume. Delhi Police have logged over 350 noise and traffic complaints within days this season, flagging high-decibel processions moving through ITO, Anand Vihar, Dhaula Kuan, Mehrauli and the Outer Ring Road. (Credit: PTI)

That gap between the written limit and the sound on the street carries a real health cost. The US National Institute for Occupational Safety and Health recommends no more than fifteen minutes of exposure a day at 100 decibels before hearing damage becomes likely. The World Health Organisation sets an even more cautious bar, noting that sound at or below 70 decibels is unlikely to cause hearing loss even after long exposure, while anything past 85 decibels can begin to damage hearing over time. (Credit: PTI)

The decibel scale is logarithmic, so these jumps matter more than they sound. A rise from 90 to 100 decibels roughly multiplies sound energy tenfold, meaning a truck running at 100 decibels isn’t a little louder than the 55-decibel limit — it’s an entirely different order of exposure.

According to the US National Institute on Deafness and Other Communication Disorders, this damage happens inside the cochlea, where sound vibrations are converted into signals the brain reads as hearing. Loud exposure destroys the tiny hair cells responsible for that conversion, and these cells never grow back. The damage can be sudden, from one very loud event, or gradual, building over months of repeated exposure — and it is often permanent. Ringing or buzzing in the ears, called tinnitus, is usually the first warning sign.

Hearing is not the only thing at risk. Research published in the American Heart Association’s journal Circulation Research links sustained noise exposure to disrupted sleep, elevated stress hormones, and higher long-term risk of high blood pressure, heart disease and stroke. Studies reviewed in the journal Hypertension describe how loud, unpredictable noise, especially at night, keeps the body’s stress response switched on even during sleep, straining the heart and blood vessels over time.

While authorities have put in place strict guidelines for DJ vehicles accompanying Kanwariyas, several videos circulating on social media appear to show violations ranging from oversized sound systems and loud music to DJs obstructing roads and causing gridlock.

The problem isn’t the absence of rules, it’s that a 55-decibel limit means little without consistent measurement against speaker trucks capable of running several times louder. As the research on hearing and heart health makes clear, that gap on Delhi’s streets each August isn’t just a civic inconvenience. It sits well within levels doctors have long flagged as harmful.