This is the song from the Hindi movie 'Rock On!' the music has been composed by the trio
Shankar Mahadevan, Ehsaan Noorani and Loy Mendosa (Official Website -
The Singer is also the same person who acted as the lead vocalist of the band called 
featured in the movie, Farhan Akhtar

[These chords were written by me for a friend who wanted to play this for a fest, and
he was a real greenhorn I wrote the Chords EXACTLY under the parts of the words to get him
change chords in time]

The song is in C major... with occasional changes :) i'm pretty sure it's 100% correct

Notes:

Hold the Open Chord shapes for the following:
Em C Dm

Hold Barre chords for the following:
F G Bb Bm

-----------------------------------------------------------------------
Tum ho to gata hai dil
       C
Tum nahi to geet kahaan
      Dm           G
Tum ho to hai sab hasil
       C
Tum nahi to kya hai yahan
      Dm              G
Tum ho to hai sapno ke jaisa hasin Ek sama
F                Bm            Em  F  C

Jo tum ho to
   G
Yeh lagta hai
    Em
Ke mil gayi har khushi
   Dm       F

Jo tum na ho
   G
Yeh lagta hai
    Em
Ki har khushi main hai kami
   Dm              F
Tum ko hai mangti
G

Yeh zindagiiii....iiiii.....OOOO...oooo..
         C        Em        F      C

O  ho  o  ho
Dm     Bb
Oo  O  o  ho
C
Woh o  ooo  o
Dm     Bb
Oo  O  o  ho
C

Tum ho to Rahein bhi hai
       C
Tum nahi to raste kahaan
      Dm            G
Tum ho to yahan sabhi hai
       C
Tum nahi to kaun yahan
      Dm           G

Tum ho to hai har ek pal meherbaan Yeh jahaan
F                 Bm          Em   F   C


Jo tum ho to
   G
hawa main bhi
  Em
Mohabbaton main rang hai
  Dm            F

Jo tum na ho
   G
To phir koi
   Em
na josh na umang hai
   Dm       F
Tum mile to mili
G

Yeh zindagiiii....iiiii.....iiii...iiii..
         C        Em        F      C

O  ho  o  ho
Dm     Bb
Oo  O  o  ho
C
Woh o  ooo  o
Dm     Bb
Oo  O  o  ho
C