Unfazed by the controversy surrounding his nationality, World chess champion Viswanathan Anand looked cheerful as he arrived to a grand reception at the International Congress of Mathematicians in Hyderabad on Tuesday.

He may be upset over the Union Human Resources Development ministry questioning his nationality, but Vishy did not show it.

The chess wizard enthusiastically walked into the huge hall at the Hyderabad International Convention Centre to simultaneously take on 40 mathematicians from across the globe in a game of chess.

Meanwhile, Anand has agreed to accept the Doctorate at his convenience, HRD Minister Kapil Sibal said.

Earlier this year, in May, Anand won the World Chess Championship, beating Veselin Topalov in the final game of the 12-game tournament in 56 moves, in Sofia (Bulgaria). He clinched the crown by a point: 6.5 - 5.5 to retain the title he won in 2008.

Anand held the FIDE World Chess Championship from 2000 to 2002, at a time when the world title was split. The 40-year-old became the undisputed World champion in 2007 and defended his title against Russian Vladimir Kramnik in 2008, thereby becoming thee first player in chess history to have won the world title in three different formats: knockout, tournament, and match.

The University of Hyderabad had planned to confer an honorary doctorate on Anand but after the HRD ministry raised doubts over his citizenship, it delayed its plans.

Hailing from Tamil Nadu, Anand made Spain his second home for some years now but continues to hold an Indian passport.

Reacting to the controversy, Vishwanathan's wife Aruna said they were not disappointed but irritated at the developments.

"I don't think we are disappointed, it is just that it is irritating to answer these questions. Anand has always had an Indian passport and is still an Indian passport holder. So restating the obvious is a bit irritating.

"I was asked to send a copy of Anand's passport which I did. That is the only piece of information I have. I don't know what transpired between them. Every time you look at him win, you see an Indian flag right behind him that proves that he had an Indian passport and I don't understand from where this is coming and why it has been made an issue.

"Receiving a doctorate degree while being in Hyderabad would have been nice but I think that moment has passed," she said.

Aruna said, "An issue has been made out of a complete non-issue. I don't understand where this ambiguity has come in, why this doubt should arise in somebody's mind (about Anand's nationality).

"The doctorate was supposed to be conferred yesterday itself. So, I wish, the matter had ended yesterday itself and not dragged to become such a controversy," she said.

Asked when the chess champion would be able to accept the honour, she said, "At present, it would be difficult to accept it because his schedule does not permit it as he is due to travel for his next round of tournaments. His calendar is busy till February as the focus is back on chess.

"So, may be at a later date, if it is mutually convenient, we will see if it is possible," she said.

"The honorary doctorate to Viswanathan Anand has not been stalled or denied. It has only been delayed. But we are extremely embarrassed over this," an upset head of the University of Hyderabad's mathematics department Rajat Tandon said.

He said the HRD Ministry has not yet responded to their proposal for awarding the honorary doctorate to the world chess champion.

"The file is still with the ministry," Tandon said, adding, "We apologise to Anand for this."