This is a gray area. of the original screenplay. While downloading a subtitle file for a personal backup of a DVD you own is generally accepted as fair use in many jurisdictions, downloading subtitles for a pirated copy is not legal.
: A significant portion of the humor relies on Rahul’s inability to understand Tamil. For many viewers, especially those not fluent in both Hindi and Tamil, English subtitles (or other regional translations) are essential to catch the "hidden" jokes made by the local characters at Rahul's expense. chennai express subtitle