At their level of play, a draw for black is well worth having and represents a lost opportunity to win for white. At my level, not so much.
Still, from my (admittedly) limited analysis, Anand (black) had the initiative, had his knights developed, working together and tying white into knots, and had put white on the defensive, even forcing him to ‘undevelop’ his queen bishop back to its initial square. I am sure that there were moves that would haved helped white, but Anand was reluctant to press the issue. I think Carlsen was happy to get the draw.