alt Hacker NewsName constraints are intended for organizations which want to issue publicly-trusted certificates for their own domains. Name constraints are already widely supported and name constrained sub-CAs exist for this purpose in the WebPKI.
eMudhra is not such a case. They are a root CA that issues certificates to the general public all over the world. In fact, they are now the preferred vendor for numerous US universities via InCommon[1]. There is no way to meaningfully name constrain them.
Can you share any insight about how an Indian CA became the preferred vendor for US universities despite the existence of LetsEncrypt? I know this is kind of a dumb question.