Just imagine a country that did not allow you to buy a laptop with pre-fitted batteries. A heavy user like me would like a standardized external battery in that case, but many won't. The limitations on the design are huge. I am not arguing against swappable batteries.
With electric cars being approx 2 times costlier in India, I do not think taxis would be a use-case for that. They are a business and they need to look at practical cost-benefit and they will not be the first ones to jump to electric.
On top of that only 5-10% of India's population can afford to be generally environment friendly in an impactful way. And only 1 or max 2% can afford the huge upfront premium on electric cars.
The Indian government needs to create less restrictive and less taxing policies towards electric but it creates policy quagmires, has a very small tax base and hence is tax-greedy overall.