Mumbai: The latest data from the Brihanmumbai Municipal Corporation’s (BMC) Epidemic Cell has revealed a mixed trend in monsoon-related illnesses this year. While cases of malaria and chikungunya have risen sharply, dengue and several waterborne diseases have shown a decline compared to the same period last year.

Between January and September 15, 2025, Mumbai reported 6,277 malaria cases, up from 5,182 cases recorded in the same period in 2024. The surge was most evident in August, with 5,706 cases this year as against 4,021 last year. Chikungunya cases also saw a significant increase, rising to 542 cases from 366 reported in the January–September period of 2024.

In contrast, dengue cases have seen an overall decline, with 2,724 cases reported until September 15 this year, compared to 3,435 in 2024. August, however, recorded a marginal rise, with 2,319 cases in 2025 compared to 1,979 last year.

Waterborne diseases displayed a mixed trend. Gastroenteritis cases fell to 5,989 from 6,599 recorded last year, with August alone showing a decline from 6,133 cases in 2024 to 5,774 this year.

Hepatitis cases, however, rose slightly to 913 from 791 last year. Covid-19 cases continued to drop significantly, with just 1,116 reported so far this year compared to 1,837 in 2024.

BMC officials attributed the trends to aggressive preventive measures, including house-to-house fever surveys covering more than 22 lakh residents across 4.7 lakh households in the first half of September.

Vector-control campaigns were intensified to eliminate mosquito breeding sites, while hospitals conducted cleanliness drives to curb infections.

Health experts cautioned that monsoon-related conditions such as waterlogging, humidity, and overcrowding continue to trigger seasonal illnesses.

Authorities have urged citizens to maintain hygiene and clear stagnant water to prevent further outbreaks.