New Delhi, May 14 (IANS) Prime Minister Manmohan Singh Thursday said Viswanathan Anand, who retained his world chess champion title for the fourth time, has made the country proud.

In his congratulatory message, the prime minister said: "I am delighted to salute you at your fourth World Chess Championship triumph within a decade."

"You have made the country proud and I join millions of admirers of the game of chess in celebrating your magnificent triumph," Manmohan Singh said.

"I understand that your championship game in Sofia was played under the most difficult circumstances but you proved once again that you remain the grandest of Grand Masters," he added.

Anand had a difficult time reaching the venue in Sofia, Bulgaria, due to the volcanic ash from Iceland that led to flight cancellations all over Europe.

Anand had to take a 40-hour long tiring road journey to reach Sofia.

This is Anand's fourth world chess title. He had previously won in 2000, 2007 and 2008.