A significant decline in dissolved oxygen levels has been observed in Pashan Lake, Pune, leading to recent fish deaths and raising alarms about water quality and pollution. Water samples collected by the Pune Municipal Corporation (PMC) on April 10 indicate that while most chemical parameters remain stable, dissolved oxygen levels have decreased compared to samples taken in late December 2025 and January 2026. Low dissolved oxygen is detrimental to aquatic life and is a primary cause of fish mortality. This situation has been exacerbated by reports of untreated sewage entering the lake, likely due to a malfunctioning sewage treatment plant. In response, the Maharashtra Pollution Control Board (MPCB) has initiated an independent investigation, with officials inspecting Pashan Lake and nearby sewage treatment facilities. Balasaheb Kukde, the regional officer for MPCB Pune, stated that preliminary inspections were conducted on April 10, and water samples were collected for further analysis to ascertain the exact cause of the oxygen decline. Authorities are poised to take further action based on detailed test results, while civic officials are devising corrective measures to mitigate environmental damage.