At least 21 international organisations have written to Chief Justice DY Chandrachud and requested the Supreme Court to speedily resolve the pending case filed by the Directorate of Revenue Intelligence, investigating Adani Group firms for alleged overvaluation of Indonesian coal imports.

The letter comes after a report by the London-based Financial Times, citing documents from George Soros-backed Organized Crime and Corruption Reporting Project (OCCRP), alluded to a "fraud" by the Adani Group by selling low-grade coal as high-value fuel in 2013.

Contending that they stand firmly against the continued use of fossil fuels, the organisations said the Financial Times report provided fresh and detailed evidence of the passing off of "low-quality coal as far more expensive cleaner fuel" by the Adani Group in transactions with Tamil Nadu's Tangedco.

The 21 international organisations that have written to Chief Justice Chandrachud are Australian Centre for International Justice, Banktrack, Bob Brown Foundation, Culture Unstained, Eko, Extinction Rebellion, Friends of the Earth Australia, London Mining Network, Mackay Conservation Group, Market Forces, Money Rebellion, Move Beyond Coal, Seniors for Climate Action Now, Stand.earth, Stop Adani, Sunrise Movement, Tipping Point, Toxic Bonds, Transparency International Australia, W&J Nagana Yarrbayn Cultural Custodians, and Queensland Conservation Council.

While the Adani Group has denied all allegations, the news report has been cited by opposition leaders, including former Congress chief Rahul Gandhi, to demand a joint parliamentary committee probe into the alleged wrongdoing.

A spokesperson for the group said the quality of the coal was independently tested at the point of loading and discharge, as well as by customs authorities and Tamil Nadu Generation and Distribution Company (Tangedco) officials.

"With the supplied coal having passed such an elaborate quality check process by multiple agencies at multiple points, clearly the allegation of supply of low-quality coal is not only baseless and unfair but completely absurd," the spokesperson said.

"Moreover, the payment is dependent on the quality of coal supplied, which is determined through the testing process," he said and added tests for quality of consignment in question had yielded results within permissible limits.

The group also stated that the vessel cited in the report to have carried the coal in December 2013 had not been used for shipping coal from Indonesia before February 2014.

In an affidavit to the top court, the Directorate of Revenue Intelligence had earlier reiterated its stand to resume investigations into the Adani Group for alleged overvaluation of coal imports.

In March 2016, the Directorate of Revenue Intelligence initiated a probe against a few Adani Group companies for alleged overvaluation of coal imports from Indonesia between 2011 and 2015.

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