As many as 85 new dengue cases were reported between October 19 and 26 in the city, a Kolkata Municipal Corporation official said on Friday.
Since January, 1,017 cases have been recorded, 226 more than during the same period last year.
KMC officials said there has been a surge in dengue cases since Durga Puja. Nearly 70% of the cases reported this year are from south Calcutta.
Out of 114 wards, 35 have been identified as vulnerable, including neighbourhoods like Tiljala, Palm Avenue, Mayfair Road, Ballygunge Park Road, Panditya Road, Ahiripukur First Lane, Beltala slum, and Topsia.
“Stagnant water in small containers such as cups, plates, or coconut shells can turn into mosquito breeding sites for Aedes aegypti mosquitoes,” said a civic official.