According to the Consular Department of the Russian Foreign Ministry with reference to the website of Uzbekistan Airways, the ban is connected with the decision of the aviation authorities of India.
According to information on the Uzbekistan Airways website, citizens of India, Nepal, Bhutan and the CIS countries are allowed to fly from Uzbekistan to India, with the exception of citizens of the Russian Federation.
If the passenger is currently in Uzbekistan, you should contact the Central Air Ticket Offices of Uzbekistan Airways for a refund of the cost of tickets.