Raags in Indian Classical Music are identified by five distinctive characteristics. Aaroha (Ascent), Avaroha (Descent), Pakad (Flow), Vaadi (Most important note) and Samvaadi (Second most important note). Almost each raag will have all of these five components associated with it except for extremely rare raags where there is no specific Aaroha and Avaroha defined. Each of these five characteristics are extremely important in their own respect. Many raags have the same notes and can also possibly have the same Aaroha and Avaroha, but what seperates them is the Pakad, Vaadi and Samvaadi. This makes is very difficult to predict the raag of a light music song just looking at the notes. There are numerous examples in which you can see that the song consists of the notes of one particular raag however it belongs to another raag, because of the flow of the notes (Pakad).

Another level complexity gets added to the equation beause light music typically doesnt follow the rules of Indian Classical Music. It has the liberty of using notes that are not present in the raag or even the liberty of changing the Aaroha, Avaroha and Pakad. In order to add a little spice to the song, the composer may add extra notes to it. This not only embellishes the composition but also makes it unique.

Another most important aspect of light music is to give due importance to the lyrics. A composer would never want to compose a sad song in a very joyous romantic raag. In order to adhere to the beauty of the lyrics it becomes imperative to maintain the mood of the poem. In order to achieve this, a composer may have to change the raags multiple times in a song, sometimes, even in the same line.

Having said that, its not uncommon to find some songs that follow all the rules and regulations of a particular raag. In that case its an open and shut case to identify the raag of such song.

Now it can be clear why its difficult to classify a song in a specific raag. So the next time you hear the song and cannot identify the raag, dont worry you are not the only one. Just enjoy the music and the composition.