HDFC BANK ADR REPRESENTING THREE ORD SHS – US40415F1012
For the NYSE ADSs/ADRs to be ISA qualifying, the question is whether the underlying shares themselves are ISA qualifying.
The evidence I’ve found (link below from the company website) is that the underlying shares are listed on the Bombay Stock Exchange and the National Stock Exchange of India (NSE) which you also identified below. Neither of these stock exchanges are HMRC designated recognised stock exchanges (as per the usual lists that you have identified below).
So, on that evidence, it appears that the underlying shares are not ISA qualifying.
On that basis and going by the usual ISA rules, if the underlying shares are not ISA qualifying then any depository interests representing the shares (such as these ADSs on the NYSE) will automatically not be ISA qualifying.