It was happened with me also at Mumbai​ airport on 24th June. I was having Qatari riyal for paying custom charges at bank but he refused to take Qatari riyal and there is a written notice also at the counter stating that we do not accept Qatari riyal. Indian government please do something and instruct them properly. Unfortunately I don't had any Indian money at that time and I exchanged at a private money exchange and what I got is only 13rupees for one riyal.