Definition 1 of 1
The usage became popular sometime in the mid-80s, when Doordarshan, the television channel run by the Indian gorement started broadcasting feature films produced in the native languages of the Indian states. The films were usually broadcast with subtitles.
Regional languages are usually known to natives of a particular state only, and residents of other states need some sort of lingua franca to be able to understand other regional languages. Knowing English and Hindi can be helpful.
"It is very easy you know. Auto drivers also speak English, not just regional language!"