Singh attracted worldwide attention when he completed the Scotiabank Toronto Waterfront Marathon on Oct. 16.
But Guinness World Records told the BBC it won't recognize claims that Singh is the world's oldest marathon runner, because he can't show a birth certificate from 1911.
Singh has a British passport showing his date of birth as being April 1, 1911, as well as a letter from the Queen congratulating him on his 100th birthday.
A letter from Indian government officials state that no birth records were kept in 1911.
It took Singh over eight hours to cross the finish line, where he was met by a throng of media, supporters, family and friends.
Three days earlier, Singh claimed another eight records for 100-year-old men in eight track and field distances from 100 metres to 5,000 metres.
It appears those records will be recognized by World Masters Athletics.
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