New Delhi: The CBI has filed a closure report in a corruption case against former Union environment minister Jayanthi Natarajan over the diversion of forest land for a steel plant in Jharkhand in violation of laws in 2012, officials said.

After six years of probe, the Central Bureau of Investigation (CBI) filed the closure report before a special court last week as it could not find enough evidence in the case to proceed with prosecution, the officials said.

The federal probe agency had registered the case against Mr Natarajan, the then managing director of Electrosteel Casting Limited (ECL) Umang Kejriwal and the company on September 7, 2017, after a three-year-long exhaustive preliminary enquiry it had registered in 2014 on the Supreme Court's directions.

The CBI had registered the FIR based on enquiry findings, which allegedly showed that ECL had signed a memorandum of understanding (MoU) with the Jharkhand government for setting up a steel plant in Jharkhand in 2004.

In 2006, the state government sought the Union environment and forests ministry's approval for diverting 55.79 hectares of forest land for non-forestry use out of the total area of 192 hectares in favour of ECL, the preliminary enquiry (PE) had found.

The Forests Advisory Committee, the apex body for approving diversion of forest land, had rejected the proposal twice on the ground that the area where mining was proposed to be carried out was part of the core zone of the Singhbhum Elephant Reserve and critical for wildlife conservation.

The agency had alleged that permission for the diversion of land was also initially denied by former minister of state for environment Jairam Ramesh.

Former Congress leader Mr Natarajan was the minister of state with independent charge of the ministry between 2011 and 2013. She resigned from the Congress in 2015.

In 2011, the then chief minister of Jharkhand again sought a "pragmatic" look into the diversion of forest land, considering that the steel plant was being developed in the most underdeveloped region, the FIR had said.

Mr Kejriwal met Mr Natarajan in September 2011 to present the case. After the meeting, Mr Natarajan sought a detailed report from the Jharkhand government. Once the report was brought for Mr Natarajan's consideration, the then director general of forests and special secretary (DGF&SS) advised her to refer the matter back to the Forest Advisory Committee, the FIR had said.

Without adhering to the advice, Mr Natarajan allegedly approved the diversion of land in a detailed order on February 4, 2012, the CBI FIR had said.

"Jayanthi Natarajan, the then minister of state for environment and forests, accorded the approval for diversion of 55.79 hectares of forest land for non-forestry use to ECL, though the same had been rejected by the earlier minister of state ... without any change in the circumstances after rejection," the FIR had alleged.

The special court where the closure report has been filed will now decide whether to accept it, resulting in a clean chit to the former Union minister, or reject it, asking for further probe by the agency.