Film music in India started with the 1931 film, Alam Ara. The songs of the films were very similar to light classical music. But it was during 1940’s that Indian film music formed its own style by combining traditional Indian elements and western music.
In the early film songs, the songs were woven into the story line. Actors sung their own songs. Such actor singers like Suraiya, K.L. Saigal went on to become the stars of that era. Then with the introduction of playback recording came the era of playback singers. Actors just lip synched to the songs sung by professional singers like Lata Mangeshkar, Mohammed Rafi, Kishore Kumar etc. These songs were associated with rhythm and melody.
Later on film songs became more dance based. Peppy, fast paced and heavily westernized film music became the norm in the industry. No longer was it necessary for the songs to be associated with the story line.
In Indian film music, even though there were film songs in several Indian languages, it was the Hindi songs that dominated the scene.
Earlier traditional Indian instruments like Tabla, Harmonium, Sarangi, Shehnai etc. were used to provide music to the songs. Classical Indian music also had a strong presence in the film music. But in recent times traditional instruments have been replaced by electronic synthesizers. Today the film music is based on pop, reggae, disco, rap etc.
With the popularity of its songs spreading across continents, Indian film music has gone global. Even Hollywood movies have been known to borrow Indian film music.