Flamingos arrive, but skip major Navi Mumbai lakes as toxicity rises

Navi Mumbai: Environmentalists have raised alarm after flamingos were seen skipping three key wetlands in Navi Mumbai—DPS, NRI and TS Chanakya lakes at Nerul—saying the water bodies have turned toxic.

Birders on Tuesday and Wednesday reported flocks flying over DPS Lake without landing, while activists said the birds appear to be “assessing and avoiding” habitats that were once prime feeding grounds. The sites are satellite wetlands of the Thane Creek Flamingo Sanctuary.

Laboratory tests commissioned by NatConnect Foundation point to severe deterioration. Total Dissolved Solids (TDS) ranged between 17,000 and 23,000 mg/L, far above the healthy level of around 5,000. pH values exceeded 9, indicating alkaline stress. Biochemical Oxygen Demand (BOD) was recorded at 14.8–23.6 mg/L against a safe 3–5 mg/L, while Chemical Oxygen Demand (COD) reached 47.5–73.5 mg/L, confirming chemical contamination.

“These indicators tell one story—the water is not moving as it should in a healthy intertidal wetland,” said NatConnect director B N Kumar, pointing to disrupted tidal flow.

According to activists, while high tide brings seawater into the wetlands, the outgoing flow is too weak to flush out pollutants. Drainage channels at higher levels are trapping contaminated water, leading to stagnation and algal blooms.

In response, the forest department has launched “Operation DPS Flamingo Lake cleanup,” removing 500–600 kg of algal sludge daily, with over 2.5 tonnes cleared so far.

Environmental groups have welcomed the move but cautioned that it addresses only surface symptoms.

“This is a good beginning, but we have miles to go,” Kumar said, calling for structural restoration of tidal exchange, including lowering drainage channels.

Activists, including Rekha Sankhala of Save Mangroves and Flamingos Forum and Sandeep Sareen of Navi Mumbai Environmental Preservation Society, have demanded continuous monitoring and long-term ecological restoration, warning that periodic clean-ups will not prevent recurrence.

They also flagged governance lapses, alleging poor enforcement of National Green Tribunal directives on wetland protection and unchecked urban pressures.

The ecological impact is already visible. Flamingos rely on algae and micro-organisms sustained by balanced water conditions. As pollution rises, the food base collapses, turning feeding grounds inhospitable.

“The birds are a signal. If they are not landing, something is seriously wrong,” an activist said.

Campaigners have urged immediate state intervention, calling the wetlands a critical urban buffer for flood control, biodiversity and groundwater recharge.

“Once lost, these ecosystems cannot be restored within our lifetimes,” Sankhala warned.