What Happened
- Lonar Lake in Buldhana district, Maharashtra — India's only known basaltic meteor impact crater and a Ramsar-designated wetland — faces an unprecedented ecological crisis due to rapidly rising water levels caused by intrusive freshwater inflows.
- Extensive deep borewell drilling in the surrounding catchment has pierced impermeable basalt layers, activating underground aquifers that now channel freshwater into the crater through newly formed subsurface springs.
- The ecological impact is severe: the lake's pH has dropped from ~11.5 (strongly alkaline) to ~8.5, threatening endemic alkaline-adapted microorganisms; fish have been able to survive in the lake for the first time on record; and algae growth triggered by elevated nitrogen and phosphorus is blocking oxygen.
- Nine of fifteen ancient temples around the crater rim have been submerged, including the historically significant Kamalja Devi temple.
- IIT Bombay has been brought in to probe the causes; experts propose diverting and treating the spring water for local use to stabilise the lake. The Nagpur Bench of the Bombay High Court has taken suo motu cognizance of the issue.
Static Topic Bridges
Lonar Lake: Geological and Ecological Significance
Lonar Lake is approximately 50,000 years old and formed when a meteorite struck the basaltic Deccan Trap plateau. It is one of only four known hypervelocity impact craters in basaltic rock worldwide (the other three are in southern Brazil). This geological uniqueness makes it scientifically irreplaceable — its silica-poor basaltic substrate and resulting alkaline chemistry create an ecosystem that does not exist anywhere else in India.
- Location: Lonar town, Buldhana district, Maharashtra (79 km from Buldhana city)
- Age: ~50,000 years (Late Pleistocene)
- Crater diameter: ~1.8 km; lake depth: ~150 m at deepest point
- Lake area: ~1.13 sq km; Wildlife Sanctuary area: 365 hectares (lake: 77.69 ha)
- Geological context: Deccan Traps basalt — the same formation that covers much of peninsular India and is associated with the Cretaceous–Paleogene mass extinction event (~66 million years ago)
- Scientific value: Hosts extremophile microorganisms — magnetic bacteria and methane-eating (methanotroph) bacteria adapted to high-pH, saline conditions, with implications for astrobiology research
Connection to this news: The drop in pH from 11.5 to 8.5 — a shift of 3 pH units representing a 1,000-fold change in alkalinity — directly threatens the extremophile community that makes Lonar ecologically unique and of international scientific importance.
Ramsar Convention and Wetland Protection
The Ramsar Convention on Wetlands (formally: Convention on Wetlands of International Importance Especially as Waterfowl Habitat) is an international treaty adopted in Ramsar, Iran in 1971. It entered into force in 1975. Sites designated under the Ramsar Convention are called "Ramsar sites" or "Wetlands of International Importance" and countries are obligated to maintain their ecological character and promote their "wise use." Lonar Lake was designated a Ramsar site on November 11, 2020, becoming Maharashtra's second Ramsar site.
- Ramsar Convention: 1971 (adopted); 1975 (in force); 172 contracting parties as of 2024
- India's Ramsar sites: 82 (as of 2024, largest number of Ramsar sites in South Asia)
- Lonar Lake: Designated November 11, 2020; Ramsar ID: 2441
- Maharashtra's other Ramsar site: Nandur Madhmeshwar (Nashik)
- "Wise use" principle: Sustainable utilisation of wetlands for the benefit of humanity in a way compatible with the maintenance of the natural properties of the ecosystem
- Montreux Record: A Ramsar list of threatened wetland sites; Lonar is not currently on it, but the current ecological changes may qualify it
- Obligation: Ramsar parties must notify if ecological character of a listed site has changed/is likely to change
Connection to this news: The pH collapse and loss of endemic species at Lonar — a designated Ramsar site — could constitute a breach of India's Ramsar obligations to maintain the ecological character of listed wetlands.
Wildlife Sanctuaries and the Wild Life (Protection) Act, 1972
Under the Wild Life (Protection) Act, 1972, a Wildlife Sanctuary (WLS) is a protected area where habitat and wildlife are protected, but some human activities — grazing, limited collection of forest produce — may be permitted (unlike National Parks where all human activity is excluded). Lonar Wildlife Sanctuary was notified by the Government of Maharashtra on June 8, 2000, covering 365 hectares.
- Lonar WLS notified: June 8, 2000
- Area: 365 hectares total (lake: 77.69 ha within the sanctuary)
- WLS vs National Park: In a WLS, the collector can allow grazing, minor forest produce collection, and limited human activity; in a National Park, no such rights exist
- WPS Schedule for key species in Lonar: Flamingos (lesser and greater) — Schedule IV; migratory birds — Schedule IV; crocodiles (mugger) — Schedule I
- Managing authority: Maharashtra Forest Department
Connection to this news: Despite being a Wildlife Sanctuary since 2000 and a Ramsar site since 2020, the borewell drilling in the catchment zone — which is causing the water level rise — appears to have occurred without adequate regulation, exposing governance gaps in the protected area's buffer zone management.
Deccan Traps and Basaltic Aquifer Systems
The Deccan Traps are a massive volcanic plateau covering approximately 5 lakh sq km of peninsular India (Maharashtra, parts of MP, Gujarat, Karnataka). The basalt bedrock, formed from volcanic eruptions ~66 million years ago, is generally impermeable — which is why Lonar's crater has retained its unique water chemistry. The recent borewell drilling has apparently penetrated fractures or weathered zones in the basalt, connecting the crater to the regional groundwater system.
- Deccan Traps area: ~5 lakh sq km across peninsular India
- Groundwater in Deccan basalt: Hard rock aquifers with low to moderate yield; dependent on fractures and weathering zones
- Borewell crisis: India has one of the highest rates of groundwater extraction globally; Central Ground Water Authority (CGWA) regulates borewell drilling but enforcement in rural Maharashtra is weak
- Relevance to Lonar: The basalt's natural impermeability is what isolated Lonar's alkaline water chemistry for ~50,000 years; borewell penetration has breached this geological seal
- Central Ground Water Board (CGWB): Under Ministry of Jal Shakti; monitors groundwater levels nationally
Connection to this news: The environmental crisis at Lonar is ultimately a groundwater governance failure — unregulated borewell drilling in the catchment has created an anthropogenic pathway for freshwater intrusion that is undoing 50,000 years of natural geochemical isolation.
Key Facts & Data
- Lonar Lake age: ~50,000 years; one of 4 hypervelocity impact craters in basaltic rock worldwide
- Location: Buldhana district, Maharashtra; crater diameter ~1.8 km
- Wildlife Sanctuary: Notified June 8, 2000; 365 hectares
- Ramsar designation: November 11, 2020 (Maharashtra's 2nd Ramsar site)
- pH drop: From ~11.5 (strongly alkaline) to ~8.5 — 1,000-fold reduction in alkalinity
- Impact: Endemic extremophile microorganisms threatened; fish now surviving (first time on record)
- Cultural impact: 9 of 15 ancient temples submerged including Kamalja Devi temple
- Cause: Deep borewell drilling piercing impermeable basalt, activating subsurface springs
- Response: IIT Bombay investigation; Bombay HC Nagpur Bench suo motu cognizance; expert proposal to divert spring water
- India's total Ramsar sites: 82 (as of 2024)
- Deccan Traps: ~5 lakh sq km volcanic basalt plateau; formed ~66 million years ago