When we talk about Evergreen songs of Bollywood, Kumar Sanu's and Alka Yagnik's "मेरा दिल भी कितना पागल है " would be definitely at the Tops of the list.  
 

This song is from one of the top most cult classic movie SAAJAN (1991) . The cast includes Sanjay Dutt , Madhuri Dixit and Salman Khan . The song features Sanjay Dutt and Madhuri in which they travel to beautiest place of Ooty . Sanjay Dutt as Aman Verma express his feelings towards Pooja (Madhuri) through this song .
The song is written by great lyricists Sameer and the music is given by Nadeem - shravan. Kumar Sanu was nominated for filmfare and won the award for best playback singer male for this song. The melodious voice of Alka has truly capture the heart of the audience. The lyrics of this song purely expresses the beauty of Love.
This song would be definitely present in playlist of every 90's lover.
The Alka - Kumar's "मेरा दिल भी कितना पागल है " will be the best and one of the most loved song of Evergreen 90's