A mixture of these Hollywood movies
The music at the start of the movie has been 'inspired' by Tarantino's and Guy Ritchie's movies.
The air hostess working as a smuggler is from Tarantino's Jackie Brown.
The diamond angle is from Guy Ritchie's Snatch.
The hotel scene, the gangs of criminals, the mix ups are from Snatch.
The jeweler part is again from Snatch.
The part of returning the diamonds is from Snatch, only in Snatch they had to return guys.
The part of wearing burkha is again from Snatch, only in Snatch they were dressed as Orthodox Jews.
I am sure there are other scenes in Delhi Belly that have been 'inspired' by Hollywood movies.