New Delhi, Aug 7: Congress President Rahul Gandhi on Tuesday expressed grief over the death of DMK veteran leader M. Karunanidhi, saying India has lost a great son, who strode the stage of Tamil politics like a colossus for over six decades."Loved by the Tamilian people, Kalaignar strode the stage of Tamil politics, like a colossus, for over 6 decades. In his passing, India has lost a great son. My condolences to his family as also to the millions of Indians who grieve for their beloved leader tonight," Gandhi said in a tweet.Karunanidhi, 94, passed away on Tuesday evening. He was admitted to the hospital on July 28 and his condition worsened on Monday.