Over 970 dengue cases were reported in the city in the past week, according to figures announced by mayor Firhad Hakim on Friday.
"The number of dengue infections (since January) stands at 4,779," the mayor said.
A 17-year-old boy from Bowbazar died of dengue on Thursday.
Hakim had on September 22 said 3,802 dengue infections had been reported in the city since January. In the week that has passed, the number of dengue infections in Calcutta has gone up by 977.
The figures that Hakim disclosed were only for the Calcutta municipal area. The state health department has yet to disclose any figure on the number of dengue infections in Bengal, though the count is rising in many districts, too.
The CMC has identified 37 wards from where comparatively more dengue infections have been reported recently. Sources in the CMC said they have identified roads in these wards from where more fresh infections are being reported.
"While routine vector-control work will be done in other places, there will be a greater focus on the places that have been identified as vulnerable. Vector-control teams will repeatedly visit these areas," said a CMC official.
The majority of the roads identified as vulnerable are in Behela, Kasba and Jadavpur. Among them are Harish Chatterjee Street in Kalighat, Rajdanga Main Road in Kasba and Raja Rammohan Roy Road in Behala.
Sahid Smriti Colony in Jadavpur and Jodhpur Park are among the vulnerable localities.
A number of dengue deaths have been reported from Calcutta as well as districts.
Neither the Calcutta Municipal Corporation (CMC) nor the state health department has disclosed any figure on how many people have succumbed to the disease this year.
Dev Popat, 17, a resident of BB Ganguly Street in Bowbazar, died of dengue on Thursday. He was admitted to Belle Vue Clinic on September 20.
The death summary issued by the hospital mentions dengue haemorrhagic fever.
In a meeting held last week, chief secretary H.K. Dwivedi had asked all municipal bodies in the state to initiate legal action against owners of the premises where sources of mosquito breeding were found.
CMC sources said multiple properties, belonging to the state government as well as the Centre, have turned into mosquito-breeding sites.
Metro reported on Friday that the Bengal government has not disclosed data on dengue infections and deaths to the National Center for Vector Borne Diseases
Control (NCVBDC), which functions under the Union ministry of health and family welfare.
The website of NCVBDC has data on the number of dengue cases and deaths in other states till September 17.
States battling a dengue outbreak are regularly updating figures available in the public domain on the number of infections and deaths so informed decisions could be taken while framing policies and chalking out grassroots action to contain the spread of the disease.
But Bengal, in the grip of one of the deadliest outbreaks of the mosquito-borne disease, has chosen to walk a different path and keep all relevant figures under wraps.