Not even the mighty Metropolitan Museum of Art has been immune to Sept. 11 fallout.

The museum has lost about 1 million visitors this year, down from about 5 million in each of the two years before.

“There’s been so many wildly divergent reports on tourism,” museum spokesman Harold Holzer announced yesterday, before director Philippe de Montebello previewed the Met’s upcoming shows.

“The fact is we’re 20 to 25 percent lower in attendance than last year.”

Holzer said the steepest drop was from Europe and Asia.

Montebello said the museum’s acquisitions remain unaffected, as do the Met’s scheduled shows for next season, which include a big Richard Avedon retrospective in the fall.