The killer smoke in our rooms
In most Indian homes, the fight against mosquitoes begins at dusk with a matchstick. A spiral of mosquito-repellent incense, glowing red in a corner, promises a bite-free night for less than Rupees two.
But the very cure we light for comfort is filling our lungs with a chemical cocktail that regulators, doctors, and researchers are increasingly flagging as a slow-burning public health risk.
Most mosquito coils and incense sticks sold in India use pyrethroids like allethrin, d-trans allethrin, or prallethrin as the active ingredient. To make them smoulder for 6-8 hours, manufacturers bind these insecticides with sawdust, coconut shell powder, starch, and dyes.
Notably, burning one coil in a closed room releases particulate matter PM2.5 equal to smoking 75-137 cigarettes, according to studies by IIT Delhi and the Indian Council of Medical Research. The smoke also contains formaldehyde, benzene, and benzo-a-pyrene – all Group 1 carcinogens.
Ironically, India already carries 32% of the global burden of respiratory disease. In poorly ventilated urban flats and rural homes where windows are shut to keep mosquitoes out, coil smoke accumulates fast.
Pediatricians and physicians report rising cases of chronic cough, wheezing, and bronchitis in children who sleep in rooms with coils lit nightly. A 2022 AIIMS study linked prolonged exposure to reduced lung function in children under 10. For pregnant women, pyrethroid metabolites cross the placental barrier; animal studies associate prenatal exposure with neuro-developmental delays. Adults with asthma see a 30-40% spike in night-time attacks during peak mosquito season, when coil use is highest. 3. The irony of the ‘herbal’ label
To escape the ‘chemical’ tag, brands now market citronella, eucalyptus, or neem incense sticks as ‘natural’ and ‘ayurvedic’. Yet the Central Insecticides Board has no separate standard for herbal coils. Tests found that many ‘herbal’ sticks still contain synthetic allethrin, because plant oils alone evaporate too fast to last all night. The green packaging creates a false sense of safety, so families burn them even in nurseries and around infants.
Mosquito coils are regulated as ‘household insecticides’ under the Insecticides Act, 1968. The law caps active ingredient content but sets no limit on PM2.5, VOCs, or heavy metals from fillers. BIS standard IS 13546:2013 is voluntary, and enforcement is weak.
A 2024 survey of 47 brands in Delhi markets found 18 exceeded the permissible allethrin limit, and none disclosed PM emissions on the pack. Unlike cigarettes, coils carry no pictorial health warning.
Importantly, it is the poor and the lower middle class that has to pay the price for this unregulated mosquito control. In slum clusters and rural belts where drainage and stagnant water breed mosquitoes, coils are the cheapest repellent during evening and night hours.
Fans or screens are unaffordable; electricity is erratic. So the very households with the highest exposure to smoke also have the least access to pulmonologists. For a daily-wage earner, a child’s month-long cough means lost wages and debt at the pharmacy.
The way the use of mosquito coils in increasing is becomes mandatory to mark strict warnings on sale packs. All the brans need to mandate stark warnings like ‘burning in closed rooms causes respiratory harm. Use only in ventilated areas.’
Besides, a ban on ‘herbal’ claims should be imposed unless the product is proven 100% plant-based and certified. There is also a need to push for alternatives like liquid vaporizers and insecticide-treated nets. Vaporizers emit far less PM, and nets involve no smoke at all.
