Edinburgh-based international oil and gas company Cairn Energy has sued Air India in an attempt to enforce a $1.2 billion arbitration award it won in a tax dispute against India in December last year, according to a Reuters report.

A lawsuit examined by Reuters has been filed in the US District Court for the Southern District of New York that seeks to make Air India liable for the judgement that was awarded to Cairn.

The lawsuit argues that Air India is a state-owned company and is therefore “legally indistinct” from the state of India itself.

“The nominal distinction between India and Air India is illusory and serves only to aid India in improperly shielding its assets from creditors like (Cairn),” the Reuters report says, quoting the lawsuit.

In December, an arbitration body awarded the Edinburgh firm damages of more than $1.2 billion plus interest and costs.

The tribunal ruled that India breached an investment treaty with the UK and said the Government of India was liable to pay.

“Cairn is taking the necessary legal steps to protect shareholders’ interests in the absence of a resolution to the arbitral award,” said Cairn Energy in a statement.

“Cairn remains open to continuing constructive dialogue with the Government of India to arrive at a satisfactory outcome to this long-running issue.”