"When I asked about the role (to the director), she said it is about a mother of a 15-year-old daughter, who is in 10th class. I asked her, 'Do you want to give me the role of the daughter?' She replied, 'No, the mother'," Swara said at the trailer launch of the film.
Popular casting director Mukesh Chhabra was the one who had approached Swara for the film.
"I told him what kind of roles he was bringing to me... I had read the script with the intention to refuse it. Mukesh is a good friend, he asked me to read the script so I'll read it but I think I'm going to say no. But I read the script and I was like, 'Wow!'" she added.
Swara said that an actor is a "very selfish creature".
"We see our benefit and what we can do. I have read numerous scripts, but it is rare that there comes a script with so many possibilities," she added.
In the film, Swara will be seen playing the mother of a 15-year-old and shares a bittersweet bond with her while having big dreams for her, though her daughter questions her capability to give her good higher education.
About playing a mother so early in her career, Swara said: "The script was very beautiful, though everyone told me that it is a career suicide."
"I first tried to show motherly feelings to my cats, which failed, and Ashwini gave me the idea of interviewing my mother, so I actually sat her across the table, put on the recorder and spoke to my mother, it was an interesting experience for me and that changed me," she added.
The film also features Ratna Pathak Shah and Pankaj Tripathi.
It had received tremendous applause at the BFI London Film Festival (LFF) and the Silk Road International Film Festival in China, where Swara received the Best Actress Award.
"Nil Battey Sannata" is set to release on April 22.