Freshwater influx endangers India’s only meteor lake 'Lonar' and ancient temples in Maharashtra

India’s only basaltic meteor impact crater, Lonar lake in Maharashtra’s Buldhana district, is facing an environmental crisis as an unprecedented influx of fresh water threatens its unique chemistry and heritage structures, a TOI report said. Formed 50,000 years ago, the lake has long served as a terrestrial mirror for Mars and a habitat for specialised microbes.

Lonar lake, a designated Ramsar wetland, has traditionally maintained high salinity and a pH of 11.5, conditions in which no fish could survive. The lake’s isolated ecosystem and ancient temples have remained largely unchanged for centuries. Last year, fish were spotted for the first time, marking an alarming shift in its ecosystem, the report said.

Temples and heritage sites submerged

Visitors to the crater can see the impact of rising water levels firsthand. Nine of the 15 ancient temples along the shoreline are now partially or fully underwater. The idol of Kamalja Devi, the village deity, is under threat from flooding that has accelerated since last year. “The rains lasted from May until Oct last year, and for the first time, the deity herself is in danger of being lost to the rising tide,” a local forest staffer told TOI.

Human intervention and groundwater influx

According to a survey by hydrogeologist Ashok Tejankar, the lake level has risen by around 20 feet, driven by deep borewells drilled by farmers in the surrounding catchment. These wells have punctured the basalt layers, activating an underground drainage system that channels groundwater into the crater. While only two freshwater springs historically fed the lake, two additional springs now flow strongly, adding to the inflow.

Dilution of lake chemistry

The influx of fresh water is diluting the lake’s concentrated salts, reducing the pH from 11.5 to nearly 8.5. “A pH of 8.5 is close to neutral. This isn’t just a change in water level; it’s a fundamental shift in chemistry that will trigger a domino effect across the flora, fauna, and microorganisms that have evolved here over 500 centuries,” Tejankar told TOI.

Water scarcity for locals

While Lonar lake overflows, the nearby village remains dependent on scarce municipal supplies and tankers, relying heavily on the borewells contributing to the lake’s flooding, the report said.

Proposed mitigation measures

Tejankar has recommended intercepting the spring water at the bedrock level and using it to supply Lonar town after purification, which could lower the lake level and conserve the temples and ecosystem, TOI reported.

Lack of coordinated protection

Despite Ramsar designation, Lonar lacks comprehensive protection. Atul Jethe of CT Bora College noted that 40% of the village is built on the crater’s ejecta blanket, with roads, agriculture, fertilizers, and pesticides encroaching on the site. Government efforts to acquire 86 hectares for conservation have stalled due to local opposition.

Conservation challenges

While the Maharashtra government has lobbied for UNESCO World Heritage status, basic infrastructure and scientific facilities remain inadequate. The forest department is awaiting groundwater survey reports to determine possible interventions under the Wildlife Protection Act, the report said.

(With inputs from TOI)