Maharashtra: ‘Wetland emergency’ alarm as flamingo lakes turn toxic

Navi Mumbai: Climate activists have sounded a ‘wetland emergency’ alarm on World Water Day as three key flamingo habitats in Navi Mumbai have turned toxic, with laboratory tests of water samples revealing alarming results.

Activists flagged the deteriorating condition of DPS, NRI and T S Chanakya lakes at Nerul, which serve as satellite wetlands for the Ramsar site, the Thane Creek Flamingo Sanctuary (TCFS).

Water sample tests commissioned by NatConnect Foundation point to a system under severe stress, activists said in messages sent to the Prime Minister and the Maharashtra Chief Minister.

The warning is reinforced by a visible ecological signal: flamingos have not arrived this season, NatConnect Foundation director B N Kumar said in a press statement on Sunday.

Four basic indicators—TDS, pH, BOD and COD—paint a consistent picture of decline.

TDS (Total Dissolved Solids), which measures salinity and dissolved pollutants, was recorded at 17,000–23,000 mg/L, far above the 5,000 mg/L typical for healthy wetlands, indicating over-concentrated, stagnant water rather than natural tidal flushing.

pH levels above 9, against a safe range of 6.5–8.5, point to alkaline stress. BOD (Biochemical Oxygen Demand) values of 14.8–23.6 mg/L, well above the safe 3–5 mg/L, signal heavy organic pollution and oxygen depletion, while COD (Chemical Oxygen Demand) levels of 47.5–73.5 mg/L, against a norm of 20–30 mg/L, confirm significant chemical contamination.

The sample testing was carried out by Thane-based SSAS Laboratory.

“Put simply, all four indicators tell the same story—the water is not moving as it should in a healthy intertidal wetland,” Kumar said, pointing to blocked or restricted tidal flow. Instead of being regularly flushed, the wetlands are turning into stagnant, polluted basins.

For Bittu Sahgal, founder of Sanctuary Nature Foundation, the crisis raises a moral question: “How do we forgive those who participate in the desecration of such an exquisite Mumbai heritage—especially when they know it truly belongs to our children?”

Activists squarely blame governance failure. Climate activist Nandakumar Pawar said CIDCO, the town development authority, is “largely responsible for what has happened,” adding that regulators such as the Maharashtra Coastal Zone Management Authority and the forest department have “simply looked the other way.” The wetlands, he warned, are a public asset being destroyed in plain sight.

The consequences are ecological. Flamingos depend on algae and microorganisms that thrive in balanced conditions. As water quality deteriorates, the food chain collapses, turning feeding grounds into stressed habitats. While flamingos have adapted to degraded sites in the past, their absence now suggests the system may have crossed a critical threshold.

“These wetlands were our pride. Today, they are being destroyed in full view,” said Rekha Sankhala of Save Flamingos and Mangroves Forum, urging authorities to treat the situation as a public health emergency. Once lost, she cautioned, they cannot be restored within our lifetimes.

Calling for accountability, Sandeep Sareen of NMEPS said the lab results expose “toxic waters” driven by unchecked development. “CIDCO’s apathy—putting concrete over conservation—is destroying these wetlands despite court orders,” he said, warning that flamingos are “the canary in our ecosystem’s coal mine.”

“It’s shocking that these well-known water bodies have degenerated so badly—CIDCO’s deliberate neglect in a time of climate crisis has put groundwater and biodiversity at risk, and we urge immediate government intervention to save these wetlands,” said environmental activist Pamela Cheema.