As much as India can rely on Solar/Wind/Water/Other green energy sources, we would still need good storage solutions that can cater to high demand-low supply scenarios. Any country has to be least reliant on foreign countries for energy, especially for future worst-case situations. India barely has any raw lithium reserves[0] compared to other countries[1] to go for battery energy storage. (Long-term possibility: India does have abundant raw material for "some new-age" batteries like sodium-ion.) Optimistically, I think just like batteries have improved so much in the last few decades[2], we might overcome the current problems with hydrogen as well.
There are myriad other, cheaper methods. India will use many of them, in different places and scales.