Conductor of opera mounted in northern India (9)
I believe the answer is:
toscanini
'conductor' is the definition.
(Arturo Toscanini)
'opera mounted in northern india' is the wordplay.
'opera' becomes 'tosca' (Giacomo Puccini opera).
'mounted' says the letters should be written backwards (in a down clue, letters mounted up).
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' written backwards gives 'ni'.
'tosca'+'ni'+'n'+'i'='TOSCANINI'
'of' is the link.
(Other definitions for toscanini that I've seen before include "Virtuoso conductor" , "Maestro" , "Arturo --, Italian conductor" , "Old conductor" , "Music director" .)