Shashikala Siriwardene followed figures of 4-53 in India's innings with 20 as she and Chamari Polgampola (23) added 41 for the second wicket.
But once Siriwardene had fallen to Dhar's medium pace, the rest of the Sri Lanka batting order was unable to cope with India's spinners.
Neetu David and Pujare Seema claimed three wickets each before new ball bowler Jhulan Goswami returned to pick up the last and give India their fourth successive win in the competition.
"I am delighted with my team?s performance in the tournament," Raj said aftewards.
"We tried new players and experimented with different combinations during the competition. I am glad that everything worked well for us and we maintained a high level of consistency which was the perfect icing on the cake."