Form of pollution in India, car being involved (4,4)
I believe the answer is:
acid rain
'form of pollution' is the definition.
(I've seen this before)
'india car being involved' is the wordplay.
'being involved' indicates anagramming the letters (involved can mean confusing or complex).
'india'+'car'='indiacar'
'indiacar' is an anagram of 'ACID-RAIN'.
'in' acts as a link.
(Other definitions for acid rain that I've seen before include "Form of pollution" , "Harmful atmospheric fallout" , "Pollution from the sky" , "What's ecologically damaging" , "Damaging precipitation" .)