The increasing rodent population is posing a threat to the city’s infrastructure as rats are digging up the soil below, mayor Firhad Hakim said on Friday.
Hakim said a portion of the pavement opposite Haldiram’s (at the Exide crossing) is in bad shape because rats have dug the soil under it. He also referred to how the civic body had to manage the problem of rodents eating into the base of the Dhakuria flyover.
The presence of rats is also a public health risk and there could be an outbreak of diseases, Hakim warned.
The mayor said the problem will persist as long as people keep throwing food waste on streets and pavements. The civic body’s solid waste management department has to ensure that the waste is removed, but eatery owners and others must desist from throwing waste on pavements.
An engineer of the Kolkata Municipal Corporation (KMC) said the footpaths along multiple roads in the city have become undulated as rats have dug tunnels underneath, displacing the soil.
“Keep the food waste packed in your place and hand it to the waste cleaner. Stop throwing food waste on roads or pavements. The rats will come if there is food for them,” Hakim said while speaking to reporters at the end of the weekly phone-in programme on Friday.
The mayor said people may laugh and consider it to be a trivial issue, but the problems faced by the civic body are not to be neglected or overlooked.
“The footpath opposite Haldiram’s (at the Exide crossing) is in bad shape. We had to mix crushed pieces of glass with soil under the Dhakuria bridge to address this menace,” he said.
As for the slopes of the Dhakuria flyover, the portion between the deck — the surface on which vehicles move — and the road below is filled with soil. Rats dug holes in the soil, disrupting its compactness and making the road surface above undulated.
Undulated footpaths are often a result of activities of rats. If the soil below loses its compactness, it leads to the formation of cavities on footpaths, engineers said.
The paver blocks, which are gridlocked, then start moving and within a few days, a smooth footpath becomes undulated with some paver blocks rising a few centimetres above others.
“Rats get food, so they start digging holes in the soil to stay there,” said the KMC engineer.
If the compactness of the soil is lost, underground pipes too are impacted. Often what happens is that the soil under one stretch of an underground drainage pipe gets disturbed and loses its compactness, but the compactness of the soil on either side remains more or less intact.
“The stretch with disturbed soil will finally collapse. This happens over months and years,” said the engineer.
Architect Partha Ranjan Das said the brickwork in some of the old houses in Kolkata was made in a way that rats could not enter the premises. The design is called the rat-trap bond.
“Rats could cut through the first layer of brick and then enter into a void. But again there was another layer of brick. This proved effective in barring the entry of rats into houses,” said Partha Ranjan Das, an architect.
Mayor’s plea to plant saplings
Mayor FirhadHakim on Friday invited schools, NGOs and private organisations to come forward and plant saplings in the city.
It was not possible for the civic body alone to undertake plantation in all vacant spaces, the mayor said.
Hakim said it was the need of the hour to plant saplings in every space available.
The civic body has undertaken projects to plant saplings in many but it does not have the funds to undertake plantation in all available public spaces, he said.
“This is why I am asking others to come forward and join the initiative.”
An official said the KMC would entrust the responsibility of maintenance of the trees, at least for the initial years, to NGOs.
