Genre is basically a classification system - categories of creative work based on style and characteristics. In Hindi cinema you have romance, action, comedy, horror.
In music, you have Bollywood pop, indie, classical, etc.
In books same thing - mystery, romance, sci-fi, etc.
Genres help audiences find what they like and help creators communicate what their work is about quickly. They've existed forever in Indian culture too - we have Ramayana in the epic genre, folk tales, etc. Genres are useful frameworks but nowadays everything blends together. A song can be pop-rock-indie fusion, a movie can mix comedy with social message, so boundaries are blurry.