No, it's absolutely not. Placing content in the public domain takes an explicit public domain dedication; simply making it available doesn't have that effect.

(Edit: Alternatively, content can enter the public domain if all copyrights on it have expired. But that's certainly not the case here either.)

No, the code is still copyrighted by Networks Layer8 or Airtel.

Publishing or delivering it on request doesn't make it public domain.

Here is one definition of public domain: the status of a literary work or an invention whose copyright or patent has expired or that never had such protection.

How was it in the public domain?