Returning the Office of Profit bill was the most difficult decision President A P J Abdul Kalam made during his tenure in the country's highest office.

"The difficult decision is, of course, one bill -- the Office of Profit -- that bill I had to return to Parliament. As per the Constitution, a President can do it, but I happened to be the first fellow," the 75-year-old Kalam said in an interaction with PTI journalists in Delhi.

He was replying to a question as to what was the most difficult moment during his term as President.

"And also a debate was started in the nation and Parliament took a decision to establish some guidelines," Kalam, whose term as President expires on July 24, said.

The President, in May 2006, had returned the Office of Profit bill that exempted 56 posts from the purview of the bill, asking Parliament to reconsider it and to have "comprehensive and generic" criteria besides making it "fair and reasonable" and applicable in a "clear and transparent" manner across all the states and Union territories.