"A bigger field -- virtually everyone writing in English -- makes it a much tougher and more covetable prize than it was when it had only British and Commonwealth writers," Roy told PTI in an interview.
The prize worth 50,000 pounds had in the year 2013 expanded its criteria for eligibility to allow all authors who write fiction in English to enter as long as they are published in the UK. Previously only authors from Britain, Ireland, the Commonwealth and Zimbabwe were eligible.
Meanwhile in Roy's fiction "Sleeping on Jupiter", her third novel she details a tale of three feisty old women from Kolkata who embark on a holiday together.
The author says the longlist announcement came as a complete surprise. "I didn't expect it at all. It was a complete surprise and it took me a long time to convince myself it had actually happened".
More From This Section
Set in an imaginary pilgrimage sea town called Jurmuli, the fiction also dwells on the subject of violence and child abuse.
Roy, whose previous novels include "An Atlas of Impossible Longing" and "The Folded Earth" says she is not prompted by current social realites to explore themes.
"I don't ever choose a theme: it's always character and place-driven for me," says the 48-year-old author.
"I found after finishing the story that I kept thinking about a girl who occurred in it as an incidental character. A temple guide too was in that short story -- again as an incidental character. As I worked more on the two of them the novel took the shape it did," says the author.