Kumble's main concern about the referral system being trialled for the first time in this Test series is the argument whether an umpire can give an (lbw) decision by looking at a television screen.
''There are certain doubts but I guess the obvious ones,'' he said.
''Of course it can be of help if an umpire makes a mistake in giving someone out lbw when he (the batsman) has nicked it and this is shown.
''But again there are areas which really helps the umpire, but there are other area where it takes a longer time to assess a review of a decision,'' he added.
He felt that the third umpire giving lbw decisions through the Virtual Eye concept needed a closer look. While it was still early in the referral process, it was a system where more discussion is needed.