Amitav Ghosh's "Ibis" novels: History book in disguise?

In an interview In The Hindustan Times' Brunch magazine, June 26, 2011 (Sorry, no link is available), Amitav Ghosh was rightly asked if his "Ibis" novels could become a history book in disguise. His answer:

"I could never write a history book in disguise really because..because I am a novelist. I am a writer of fiction. That's what I do. To write history is a very particular thing. It calls for specific talents, which are not ma talents, you know. It's not something that can happen. First and foremost, I'm a storyteller."

I have no problem in admitting that he's an astute storyteller. But is the stuff that Ghosh has been churning out for some years now can really be called literature?