MUMBAI, Jan. 12 -- Ashok Chawla resigned on Friday as chairman of the National Stock Exchange of India Ltd (NSE) with immediate effect "in light of recent legal developments", the exchange said.

The one-sentence press release gave no details.

Chawla's resignation came on a day the Central Bureau of Investigation (CBI) told a special court in Delhi that it has obtained the sanction of the concerned ministries to file charges against him and four other former bureaucrats in the Aircel-Maxis case.

Mint first reported on 5 November that Chawla would need to step down as soon as the CBI gets the go-ahead to prosecute him. Chawla had to step down as he was no longer 'fit and proper' as per the regulations of the Securities and Exchange Board o...