"Ashwin has got variations. He can bowl almost each and every delivery, googly, off-spin, leg-spin, carrom ball. The majority of his deliveries are still off-spin. I think it's important for him to concentrate on his stock delivery. I think he has done that really well," said Dhoni when asked to compare Ashwin with unorthodox Pakistan bowler Saeed Ajmal.

"They are different bowlers. It's unfair to compare them. Ajmal has got a brilliant 'doosra' and generates a lot of pace when it goes away from a right hander. He's quite special," said Dhoni at the media conference ahead of the first Test against England starting here tomorrow.

While 26-year-old Ashwin has grabbed 49 wickets in eight Tests, including 40 at home in five games, 35-year-old Ajmal has impressive figures of 122 wickets in 23 Tests, including 24 in three Tests in the United Arab Emirates nine months ago.

Dhoni did not see any threat to the future of Test cricket played in India, though he conceded that the crowd turning out at stadia have dwindled over the years.

"It's a very competitive world out there. On week days it's very difficult for a large amount of people to come out and see because it's not easy to work for the private sector and seek a holiday to see India play. That's also a big factor," Dhoni said.

"There was a period when stadiums were houseful for Tests. Still a decent amount of people turn out for Test matches. We have seen that in the smaller cities. We got more crowds than in some of the bigger cities. I don't think it's really alarming. There is good future for Test cricket.