Also because Russia already had $50 billion stuck in Indian Rupee they cannot use. So they now use CNY of course, but even now a lot of exports still gonna be sold for USD.
They can, India will happily sell them stuff for rupees, but the problem is that Indian exports mostly don't match Russian import needs.
They can of course invest into India economy to get even more Rupees.
My best answer was to recruit Indian mercenaries for meat attacks. But it is possible that New Delhi would not like that. India doesn't suffer from a lack of young disposable men, but it also cares about its international reputation.