The officials from the city's Department of Environmental Protection said the source of the smell that was reported by 37 concerned callers this week has remained elusive despite having occurred at least three times since 2005, the New York Post said Wednesday.

"It's still a mystery," Office of Emergency Management spokesman Chris Gilbride said of the sickly sweet smell.

Gilbride said the smell was reported Monday all across Manhattan, from the Upper East Side to the Upper West Side. One Queens resident even reported smelling the odor in that New York borough.

The Post said the odor was deemed harmless in 2005 and the main suspect behind the mysterious smell remains a food processing plant in New Jersey.