Spotify doesn’t have a date yet.
From a recent Spotify earnings call (Q2 2018), the CEO of Spotify says:
Obviously it’s the big markets like Russia, India that probably will contribute the most. I don’t have any further comment on any specific launch dates on those things.
They have already set up an office in Mumbai last year, and appointed the former OLX CEO Amarjit Singh Batra as Spotify India’s head. But the launch had hit music label resistance. Considering the current challenges, Spotify may be launching in October or November this year.
Update by Spotify CEO Daniel Ek (Q3 2018):
India specifically is a very fragmented marketplace, with lots of different local labels, lots of different local publishers. Whenever we deal with licensing situations, it’s very hard for us to predict accurate timelines on the basis of multiple partnerships — just the sheer scale of number of partnerships makes it very hard to predict that, but there’s nothing that we see that prevents us from launching in India.