Wildlife & Biodiversity

Delhi has joined several Indian states in banning glue pads for rodent control. But what about poison?

Despite well-known dangers, anticoagulant rodenticides remain a popular, unregulated method to control rats in India

By Preetha Banerjee
Published: Friday 15 September 2023
Birds of prey and animals that feed on poisoned rats can die of secondary poisoning or carry the toxins into the foodchain. Photo: iStock_

The Delhi government announced directives to ban the manufacture, sale and use of glue pads that is a common but one of the most cruel methods to kill rodents. 

It joined states like Andhra Pradesh, Telangana, Madhya Pradesh, West Bengal, Arunachal Pradesh, Himachal Pradesh, Uttarakhand and some others where the method is already banned, following an advisory by the Animal Welfare Board of India (AWBI) in 2011 (and subsequently in 2021).

The products use strong glue that traps small animals running over it. These animals are unable to free themselves, attempt to chew off body parts that are stuck and die slowly due to starvation and extreme pain. 

Apart from pests like rats, mice and some insects, other small animals like squirrels and frogs also accidentally get stuck in these glue pads and die, noted the order by the director of the state’s animal husbandry unit. 

People for the Ethical Treatment of Animals (PETA) India, which sought the ban, welcomed Delhi’s move, according to a report by the news daily The Times of India

It is heartening that so many Indian states have made it illegal to use this inhuman method of controlling rodents. But, as with the unfolding debate on human-wildlife conflict in the country, it has raised some questions. 

A small section of the healthcare and hospitality industries, for instance, has complained that glue traps are more effective than alternatives like rat poison, traps and cages, at least for their purpose. 

The ban has disrupted their operations and made maintaining hygiene a challenge in hospitals, restaurants and hotels, they complained. 

In AIIMS Bhopal, for instance, the glue strips were used to protect dead bodies in the mortuary from rats, according to a letter by Dr Jayanthi Yadav, professor of forensic medicine, AIIMS Bhopal. “Controlling rat menace is an essential protocol for protecting the dead body in the mortuary. Now we are not allowed to use the sticky stripes for rat (as per PETA) [sic]. And if any dead body is harmed, the human rights commission questions us,” she wrote in a letter to the editor of Down To Earth. Bhopal banned the glue pads in May 2023. 

Most of them, however, agreed that more humane ways must and can be adopted. “It is true that rodents can become a menace but we don’t have to adopt cruel measures to control them. The pests come for food. So, keeping kitchens and stores clean can also solve the problem,” said Pranab Pal, a hotelier and hospitality industry veteran.

Rat poison, a commonly used alternative to glue pads, is also one of the most inhuman ways of dealing with rodent infestation. The ban on glue pads serve as a reminder that poisoning rats threatens predators who feed on their carcass but isn’t regulated.

Rat poison, along with glue strips, was observed to be the worst for ‘rat welfare’ in a January 2023 Oxford University study. 

“Anticoagulant poisons, which interfere with blood clotting and kill rats through haemorrhaging, can lead to extreme suffering,” it added. 

Animals that feed on rats – cats, snakes, mongoose and predatory birds like hawks and owls – are also harmed by the toxins. 

Yet, their use is quite common and AWBI has not issued guidelines for any of the alternatives of glue pads, including anticoagulant rodenticides (AR), confirmed an official of the board that is an advising body for the Union Ministry of Fisheries, Animal Husbandry and Dairying. 

Second-generation AR (SGAR) can be lethal for raptors in high doses, studies have shown. But they can also accumulate in the livers of animals and remain in the foodchain for months, thus contaminating the ecosystem. 

It is difficult to ascertain the actual number of birds of prey that die of secondary poisoning due to AR but a 2020 study found that all the red-tail hawks in their sample size "tested positive for exposure to anticoagulant rodenticides". 

“The study, published in Environmental Toxicology and Chemistry, also found that 91 per cent of the birds tested positive for two or more different types of anticoagulant rodenticides, with SGARs brodifacoum, bromadiolone and difethialone found most frequently,” according to an official blog by the Tufts University, Massachusetts, United States which conducted the research.

But there is no data quantifying the impact of ARs on birds of prey in India available at the moment, said Ashwin Vishwanathan, research associate, Nature Conservation Foundation. “Findings from studies done in other countries indicate this is a serious threat to predatory birds. Research should be conducted in the country to understand the nature and scale of the problem as well as solutions.” 

Certain SGARs are banned in the US, British Columbia in Canada and partially in the United Kingdom (effective from July 2024).

Moreover, this class of rodenticides are also toxic for humans. Of 14,867 cases reported to the National Poison Information Centre, a telephone service by the Department of Pharmacology, All India Institute of Medical Sciences, 17.06 per cent were due to rodenticides.

Poisoning is second-most common means adopted by people dying of suicide, according to a report in The News Minute. In India, some 29,408 people died of suicide by consuming poison in 2021, according to the National Crime Records Bureau. 

The problem is so prevalent in Tamil Nadu, where 7,041 people died consuming poison the same year, that the government ordered a blanket ban on rodenticides, the news portal reported. 

At the same time, the damage caused by rats, especially in an agrarian country like India, cannot be overlooked. 

Last year, more than 100 farmers in Mizoram reported that hundreds of thousands of rats ate away 524 hectares of their paddy fields from August-September, according to The Times of India. They resorted to dealing with the menace by mass poisoning of the rats, with support from the state government, the report added. 

From June to August this year, the Navi Mumbai Municipal Corporation also undertook a rat control drive and killed 27,521 rats using poison tablets to check the spread of diseases by rodents, a story in the news website The Hindustan Times noted. 

Experts feel there is a need to check the indiscriminate use of rat poison in India. More humane and safer methods may be time-consuming but have been successfully adopted to control rat populations.

The Jagannath Temple in Puri, Odisha was infested by an unusually large number of rats following the COVID-19 pandemic lockdowns, posing a threat to its wooden idols and structures, according to a report by the NDTV news portal in January 2023. 

But poisoning wasn’t an option for the authorities not only because of religious reasons but also to protect the other wildlife like monkeys and pigeons found on the premises, the story stated.

“We are laying traps to catch the rats alive and are releasing them outside according to the provisions adopted over the years,” temple administrator Jitendra Sahoo was quoted as saying.

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