Acquisition to boost its generics business in developed markets.
The deal underscores a growing trend of consolidation in Asia's wealth management industry.
Would-be investors such as KKR, the Blackstone Group and Macquarie Group are looking at buying into completed projects.
Authorities claimed that a share sale by the company to its overseas parent in 2009 was undervalued by about Rs 15,200 crore.
The planned fund could help New Delhi raise between $1 billion and $2 billion.
The buyer received poor investor response to the pricing of the share sale.
Authorities are checking deals involving more than three dozen companies.
Investors including units of Morgan Stanley and Citigroup have agreed to buy 28.3 million shares of Bharti Infratel at Rs 230 apiece.