Sale of shares in indian company by a non resident to another non resident

Dear Members

A non resident shareholder is selling his equity shares in a indian company to another non resident shareholder. 

It is understood that capital gains tax is payable by the seller non resident shareholder to government of india. 

For this is the seller required to obtain a PAN in India ?

Or can the non resident buyer of shares deduct tax at source and make net payment to the seller and deposit the tax deducted by taking a TAN in india ?

Please advise.

Regards

Dipjyoti Majumdar