I will push back on that. "India is about as diverse as southern or western europe for most dimension of diversity" is probably more fair. As diverse as europe, especially if you include the Balkans, southern europe, northern europe and "eastern" europe (in a large sense, including Georgia, and western Kazakstan), seems quite hard, for a subcontinent at least.
India has 270 languages with at least 10K speakers; Europe has ~200 languages. India has ~1.4B people; Europe has ~750M people. India has about ~2000 distinct ethnic groups; Europe has ~200.