People upset about English claim to an Indian tree (4)
I believe the answer is:
neem
'tree' is the definition.
(neem tree is a kind of tree)
'people upset about english' is the wordplay.
'people' becomes 'men' (men can refer to humanity as a whole).
'upset' says the letters should be written in reverse.
'about' is an insertion indicator.
'english' becomes 'E' (abbreviation).
'men' in reverse letter order is 'nem'.
'nem' placed around 'e' is 'NEEM'.
'claim to an indian' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for neem that I've seen before include "Exotic tree" , "Aromatic oil" , "Indian tree yielding medicinal oil" .)