I have a parallel talk scheduled on May 5 on WG4 (
https://indico.cern.ch/event/1072533/contributions/4778109/). I am currently in India. I have been trying to schedule a visa appointment, however they do not respond by phone and the visa service online application didnt show any dates available since start of April. I was able to contact them finally, early last week, through email and they informed me there are no visa appointment dates available for my intended travel dates.