A rare lake in Maharashtra created by a meteorite impact 50,000 years ago could be on the path to severe degradation. A draft notification issued by the Ministry of Environment, Forests and Climate Change in November reduced the protective eco-sensitive zone around Lonar lake in Maharashtra’s Buldhana district from 500 metres to only 100 metres.

Activist Sudhkar Bugdane, a retired college principal in Lonar, who is a member of a committee established in 2002 to conserve the crater site, said that the committee was not consulted when the Buldhana collector – who is also part of the conservation panel – and the Lonar municipal corporation sent a draft document to the central ministry recommending that the eco-sensitive zone around the lake be reduced. “I am also a committee member and they never brought it up in their meetings,” he said.

Activists said they weren't given enough time to respond to the draft notification as by the time they heard of it, the period of two months for raising objections to the notification had lapsed.

Mayuresh Prabhune, a member of the Pune-based Centre for Citizen Science, a group interested in protecting the Lonar crater, said that though the draft notification came out in November, it was uploaded on the Buldhana district website only in the first week of March. “We got to know about this from locals of Lonar,” Prabhune said. “Technically, we had 60 days to give our objections so it has already expired. But when we called the ministry, they said that we could send our objections and that they would try to do what they could.”

In 2009, Bugdane had appealed to the Nagpur bench of the Bombay high court to implement a scheme to protect the area, not just as a forest zone, but as a geological park. In 2010, the court directed stopping of all construction and development activities within 500 metres of the lake. The case is still going on. “I thought the court case was going on so did not know they would do this," said Bugdane. "They sent this proposal without thinking.”

Bugdane plans to bring up this issue in court on March 31.

One of a kind

Lonar lake is not an ordinary meteorite crash site. It has significant value for scientists studying geology, biology and even other planets.

The crater was formed when, around 50,000 years ago, a rocky asteroid or an icy comet crashed into an expanse of basaltic rock in what is now called the Deccan plateau in central Maharashtra. The crater measures 1.8 km in diameter and 150 metres in depth, and is now the site of Lonar lake, an unusually saline water body. The lake – approximately 150 km from Aurangabad – is a popular trekking destination.

According to Sarah Stewart-Mukhopadhyay, a planetary scientist at Harvard University, basaltic rock is the most common rock in the solar system. The Lonar crater is one of only two such meteorite impact sites in basaltic rock across the world – the other is in Russia. Thus, the crater offers a unique opportunity for scientists to study how small impact sites work on other rocky bodies in the solar system, such as the moon or Mars.

The water in the crater’s lake is a bounty for microbiologists – it is highly saline and has rare bacteria that thrives in extreme conditions.

The crater’s value also lies in its relatively young geological age, said Suvrat Kher, a geologist who works out of Pune. “High erosion rates on earth wipe away bits and pieces of any feature, many times making a detailed reconstruction of events impossible,” Kher wrote in his blog. “In Lonar crater though, impact features are well preserved and have proved useful in understanding cratering mechanisms.”

The crater might be even younger than earlier estimated, Kher wrote in his blog. A 2009 study of soil preserved under the ejecta blanket – the apron of material that is thrown out around the crater rim as a result of a meteoritic or volcanic impact – said it was formed a mere 12,000 years ago.

Slow decline

However, both the crater and the lake have been subject to degradation over the years. Lonar town almost directly abuts the crater and there are some slums along the northern part of the crater rim that are now being removed.

Even the water quality has been affected. A report in downtoearth.org from 2011 said that sewage from human habitation had made its way into the lake, reducing its salinity. The report said:

“The lake… has been reduced into a waste receptacle for the past several decades despite the local council declaring a 500 metre zone surrounding the lake as a no-development zone. Sewage from a slum cluster, comprising 350 shanties close to the lake, drains into the water body. Some 22 ha of dry land in the crater is being farmed, which causes water laced with pesticides and fertilizers to flow into the lake. The Lonar-Mantha road has damaged the most sensitive part of the lake’s ecosystem – the rim and the ejecta-blanket, a one kilometre area outside the crater where rock material thrown by meteoric action is deposited. A highway being constructed close by has compounded the problem.”

The report added:

“The lake’s water has been steadily losing its unique properties due to fresh water intrusion. The alkaline level of the water, recorded at 13 in the 1960s and 1970s, has dipped to below 10. Rise in nitrogen and phosphorus levels has triggered algae growth, blocking oxygen necessary for the survival of the lake’s unique population of magnetic and methane-eating bacteria.”

In 2002, the Supreme Court asked the Centre to demarcate a 10 km protective radius around all eco-sensitive zones in the country, Prabhune said. But when the states said this was not practical, the Centre decided in 2006 that these zones would be site-specific.

The wheels of government move slowly, so listing these zones only began in 2010 and are expected to be finalised this year. Local bodies, such as the municipal corporation at Lonar, created their notifications, which were approved by state governments and then passed on to the Centre. Bugdane's conservation panel was not involved in this process.

In 1999, it was the district administration in Buldhana that had first issued a notification to set up a committee to conserve the site. The panel was formed in 2002 under the chairmanship of the district collector. This is perhaps why Bugdane, also a member of that panel, is now exercised that the panel was not consulted about the demarcation of an eco-sensitive zone around the crater.

“The main reason eco-sensitive zones fail is when you involve local bodies [municipalities] in deciding boundaries," said Prabhune. "This should be a world heritage site, but for that it should first be in the national heritage list. The problem is that even in Maharashtra, people don’t know the exact significance of the Lonar crater and this knowledge is lacking in the environment ministry notification too.”

Bugdane, who is a state-certified tourist guide to Lonar, has been fighting to preserve the crater since the 1980s and is unlikely to give up now. “People keep asking for development here because there is less land,” Bugdane said. “That is why they are angry. Even I have farm land here and even I will lose if the development is restricted to 500 metres. But I still think this is more important.”