Central plan has to be introduced in the capital (5)
I believe the answer is:
lhasa
'capital' is the definition.
(capital of Tibet)
'central plan has to be introduced' is the wordplay.
'central' says to take the centre.
'to be introduced' is an insertion indicator.
The centre of 'plan' is 'la'.
'la' going around 'has' is 'LHASA'.
'in the' is the link.
(Other definitions for lhasa that I've seen before include "Tibetan holy city" , "Luxembourg's a" , "Capital of Tibet" , "foreign capital" , "Group; stripe" .)