Tum Chalo to Saara Hindustan Chale

Tum Chalo to Saara Hindustan Chale series - This was a part of Lead India Campaign of Times of India

I think it's Shankar Mahadevan's voice along with the voice of one of it's

kind Sukhwinder Singh (Sukhi).

Confirmed. It's Shankar Mahadevan, Sukhvinder Singh and the lyricist is

Gulzar. Nice initiative by Times of India. More about this here.