Nearly 65 per cent of dengue cases in the city have been reported from six boroughs, which cover places like Kasba, Behala, Jadavpur and New Alipore, Kolkata Municipal Corporation (KMC) officials said on Wednesday.
These areas are also the ones from where more number of fresh cases are being reported even now. A large number of cases are also being reported from the Topsia-Tiljala belt.
Some of the boroughs with high numbers of dengue infections are boroughs X (Tollygunge, New Alipore), XI (Garia, Bansdroni), XII (Kasba, Anandapur, Mukundapur), XIII (Behala), XIV (Kidderpore-Mominpore) and VII (Topsia-Tiljala), said a KMC official.
"About 900, out of 1,400 dengue infections, are from these boroughs," said a KMC official.
Civic officials blamed the comparatively higher infection numbers in these boroughs on a number of factors — the presence of more vacant lands where waste accumulates and more under-construction buildings that are potential sites of mosquito breeding.
"These are places where there are a good number of vacant plots. Most of these plots have turned into sites for dumping waste for residents. As a result, the plots contain many small containers where water accumulates and turns into sites for mosquito breeding," said an official.
"We have cleaned many vacant plots but the number of such plots is so huge that it becomes impossible to cover all. Also, a plot that is cleaned today again turns into waste ground in few months," added the official.
The Telegraph reported on Monday that the number of dengue cases in the city has doubled in the last fortnight. While over 700 cases were reported between January and mid-August, an equal number of cases were reported between mid-August and the end of August.
The KMC or the state health department does not release any official figures on the number of dengue infections or how many people have died from the vector-borne diseases. But many officials of the KMC, who spoke on condition of anonymity, said that the number of dengue infections has risen from 700 to 1400 within a fortnight.
Sushanta Ghosh, the chairperson of borough XII, which covers parts of Kasba, Kalikapur, Mukundapur and Patuli, said over 120 dengue cases were reported from the borough last week.
Jui Biswas, the chairperson of borough X, said about 150 new dengue cases were reported from borough X, which covers places like Tollygunge and New Alipore, alone last week.
A KMC official said these were unverified data, which meant that these were simply figures based on reports that showed the person tested positive for dengue. The KMC sends the data to the state health department with a history of the patient's travel. If it is found that the patient is from a neighbouring district or has travelled to any other district, then the case may be added to the number of infections in another district.
Ghosh told The Telegraph that canals crisscrossing the borough were also another mosquito breeding source. The flow has stopped in some pockets and mosquitoes have started breeding there, he said.
Among the deaths that have come to light this year are people who were residents of these areas.
A 32-year-old woman, who was a resident of New Alipore, passed away last week. A 10-year-old girl, who was a resident of Picnic Garden, died of dengue in July. A 13-year-old boy, who was a resident of New Alipore's Sahapur Colony, died of dengue in August.