Maybe it’s very specific then.  I used डाटामेल.भारत and xn--c2bd4bq1db8d.xn--h2brj9c.  Whois.com finds both.  Whois.icann.org serves

From: Marc Blanchet [mailto:marc.blanchet@viagenie.ca]
Sent: Thursday, June 28, 2018 18:35
To: Mark Svancarek <marksv@microsoft.com>
Cc: ua-discuss@icann.org
Subject: Re: [UA-discuss] How do I log a bug related to ICANN WhoIs portal?

works for me with either A-Label or U-Label. Marc.

On 29 Jun 2018, at 8:30, Mark Svancarek via UA-discuss wrote:

https://whois.icann.org/en does not successfully locate IDN domains even if the domain name is input as ALabels.