National Stock Exchange Chairman Ashok Chawla resigned on Friday with immediate effect after the Central Bureau of Investigation was granted sanction to prosecute him and four others in the Aircel-Maxis case. The NSE in a brief statement said Chawla had resigned “in light of recent legal developments”.

Chawla also quit as chairman of The Energy Resources Institute, The Hindu reported.

Besides Chawla, the CBI got permission from the government to prosecute two former finance secretaries, Ashok Kumar Jha and Ashok Chawla, and two serving Indian Administrative Service officers Kumar Sanjay Krishna and Dipak Kumar Singh, the Hindustan Times reported. They were members of the Foreign Investment Promotion Board that had granted approval to former Finance Minister P Chidambaram’s son to invest a huge sum in Aircel-Maxis.

The only body allowed to grant such approval is Cabinet Committee on Economic Affairs. However, Chidambaram and his son Karti have denied the charges. Chawla’s resignation came the same day that a court extended the Chidambarams’ interim protection from arrest up to February 1.

Chawla, the Chidambarams, and the other officials the CBI has been given permission to prosecute were named in the agency’s FIR filed in July. On November 26, the Central Bureau of Investigation had informed a court in Delhi that the central government has sanctioned the prosecution of Chidambaram in the case.

The Enforcement Directorate had also filed an FIR in the case.

The case pertains to clearances that the Foreign Investment Promotion Board granted the firm Global Communication Holding Services Ltd for investment in Aircel in 2006. Chidambaram was the finance minister at the time and Karti Chidambaram allegedly facilitated the payment of bribes in the Aircel-Maxis transaction.

The Enforcement Directorate, which is investigating a money laundering angle in the case, is inquiring why Chidambaram approved the investment when only the Cabinet Committee on Economic Affairs can give the green signal for such deals.