India is one of the biggest movie markets in the world and the Indian audience is crazy for movies. A number of regional film industries are successfully running in India and some of these films often end up doing great business pan-India. Bollywood has the widest reach for any of the film industry in India and often remakes regional films.
South has Malayalam, Telegu, Kannada, and Tamil film industries and the stars of these industries have a huge following worldwide. Bollywood has successfully remade these films and catered to a huge audience which has resulted in huge box-office earnings. Here's a comparison between highest grossing South Indian films and their Bollywood remakes: