Hi Aspirant,
The medium of communication should preferably be English.
However,what's important is not the use of exemplary English,but rather the use of the language to get your ideas and opinions clear.
The level of language usage is a bonus,but it shall in no way result in a disqualification of any sort.
Hope this helps.

Hello Bharat,

The preferred mode of language is English in GD - PI.
I would thereby suggest you to kindly have a talk with panel if they allows youelse need to speak in English since all are comfortable with that.
Hope it clears your doubts.
All the best