The exchanges made the procedural request after the former chairman of parent Tata Sons Ltd [TATAS.UL], Cyrus Mistry, on Wednesday said the group could face an $18 billion (15 billion pound) writedown, partly related to the acquisition of its European steel business.

"As part of the preparation of financial assets, the value-in-use of the assets of the Company is tested for impairment as per the Accounting Standards," Tata Steel said in a statement.

The company said it had nothing further to "comment or disclose."

(Reporting by Promit Mukherjee)