India has conveyed its grave concern to Switzerland for not providing information under the Double Taxation Avoidance Convention (DTAC) between the two countries. New Delhi has also threatened to drag the European nation to multilateral fora for continuing to block its requests. Information about Indians with accounts in Swiss banks has been sought by the Indian tax authorities under this convention. In a letter to his Swiss counterpart Eveline Widmer Schlumpf, Finance Minister P . Chidambaram said that there is no effective exchange of information between India and Switzerland despite a clear obligation of Switzerland under DTAC which is a matter of grave concern for India. Chidambaram reminded her of the April 2009 declaration adopted by G20 leaders stating the era of bank secrecy is over and said that if this condition continues then India will raise the issue in various multilateral fora. The two page letter dated 13th of this month was released to media today after the Supreme Court yesterday pulled up the Centre for failure to take steps during last six decades to bring back black money stashed in foreign banks.