Varthur Lake

• No Bengaluru lake met safe water standards in 2025 tests
• Most lakes rated Class D or E, unfit for human or animal use
• Experts warn of ecological emergency amid rising pollution

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Once famously known as the “land of a thousand lakes,” Bengaluru is now facing a serious water crisis. According to data released by the Karnataka State Pollution Control Board (KSPCB), none of the lakes tested between April and November 2025 met safe water quality standards.

Water samples were collected from 147 monitoring locations across the city. The results revealed that not one lake consistently qualified as safe for drinking or even bathing. The findings highlight the growing environmental stress in a city already battling water shortages and rapid urban growth.

No Bengaluru lake meets safe water category

The KSPCB classified water quality under different categories. Class A water can be used for drinking without treatment, while Class B is considered safe for bathing. Class D and E indicate heavily polluted water that is unfit for human use.

Notably, none of Bengaluru’s lakes achieved Class A or Class B status during the monitoring period. Most waterbodies were placed in Class D or E, showing high levels of contamination. Officials noted that fecal coliform levels in many lakes were several times higher than prescribed standards, making the water unsafe even for animals.

This comes despite years of investment in sewage treatment plants (STPs), lake rejuvenation projects, and sewage diversion channels. The continued poor performance raises serious questions about implementation and monitoring.

Iconic Bengaluru lakes among the worst hit

Several well-known lakes recorded alarming pollution levels. Bellandur Lake, one of the largest in the city, was rated Class E in April. It showed slight improvement during summer, moving to Class D, but slipped back to Class E by November.

Varthur Lake also fluctuated between D and E categories throughout the period. Hebbal Lake maintained a D rating for several months before deteriorating further. Other lakes such as Madiwala, Kaikondanahalli, Kundalahalli, and Ulsoor were consistently placed in the D or E categories. Sankey Tank managed to remain in Class D but did not show improvement.

The worst-affected zones were Bommanahalli and Mahadevapura, areas that have seen rapid urbanisation. Experts say untreated sewage discharge and unplanned development are major contributors to the decline.

Experts call it an ecological emergency

Environmental activist Madhuri Subbarao, co-founder of Friends of Lakes, described the situation as alarming. "Many lakes in Bengaluru are on the brink of ecological collapse. Today, we cannot point to a single lake with healthy water quality, stable ecology, or safe biodiversity. Most lakes fall below acceptable standards, with water unfit even for animal consumption,” she was quoted by NDTV as saying.

She has urged the government to create a dedicated lake restoration task force, scientifically identify pollution sources, and work closely with citizen groups.

The crisis is especially concerning as the city prepares for peak summer, when dependence on groundwater and water tankers increases. With surface water bodies declared unfit, Bengaluru faces mounting pressure to secure safe water in the months ahead.