Wow, people are coming out with well articulated, technical and very sophisticated arguments to support feasibility of exam on May 31st. I wish things to be miraculously normal soon. But boss, it's not gonna happen. Simple thing is SCHOOLS are not available, (few states already shut them till June), PUBLIC TRASPORT is not gonna resume anytime sooner, ADMINISTRATION (staff, police etc) is busy elsewhere and there is serious possibility of COMMUNITY SPREAD, and last thing UPSC is just a tiny organization(stop treating it like a god) which lacks capacity to conduct exam in current scenario.
So it has to be postponed, nonetheless 'Padhai jaari rakho, aaj nahi to Kal exam to dena hi hai'.