Unlike the instruments that have been previous taught or examined in the music of India, the harmonium is one of the most frequently used instrument that has no Indian origin. The harmonium was actually a European organ that was used in churches during the medieval time frame. The look of the harmonium then was almost similar to a piano. There is was a huge number of keys, a chair to sit down, and a foot pump for the air. This way, the musician could play the harmonium with both hands. European music requires this, it is mostly harmonic through the use of chords. A chord is when three or more notes are played simultaneously.
When the British came to India in the 18th century, they brought their harmoniums also. Although the foot pedal was still retained, the hand pumped version was introduced. When the harmonium came across to North Indian musicians, they immediately favored this instrument for few reasons. When the hand pumped version came out, it did not require foot pedals. For an Indian musician, it was discipline and practice to sit on the floor. Thus, this format of a floor organ worked well. Secondly, the harmonium was able to go with the flow of the voice pretty well. Thirdly, it was much easier to learn than sarangi. Sarangi is a bowed instrument which was used to accompany vocalists. However, it was very difficult to play. Even though one hand was required to pump air, it was not a problem, because Indian music does not have chords. Since Indian music is primarily melodic, only hand was needed to pump and one hand was needed to play the melody.
Despite its European origin, the instrument has found its use really well in an Indian musical setting. With the exception of South Indian music, the harmonium has been used in almost all genres of music in India.
The harmonium is not strictly limited to Indian styles. Western forms, in terms of chord changes, are currently integrated into the North Indian forms of music. Chord progressions introduce a different form of modality. Chord progressions, however, will not be found in North Indian classical or semi classical.