Previous dates for Adani's open offer were from 17 October to 1 November.
Musk is set to close the $44 billion deal on 28 October.
The acquisition follows WPP’s decision to merge Essence and MediaCom globally in April this year.
On 23 August, the Adani Group made an open offer to acquire a 26% stake in NDTV.
It will trigger an open offer to acquire up to 26% stake in NDTV.
