If you’re in a safe place, you should stay where you are until it’s safe to leave. You should follow any advice provided by the local authorities. If you can leave Nepal safely then you should do so.
The road to Kathmandu Tribhuvan International Airport is open and commercial flights on regular carriers like Qatar Airways and Etihad are currently operating. Get in touch with your airline or travel company for more information.
Because of the exceptional current circumstances, if you’re travelling from Nepal to a third country via India, you don’t need to get a transit visa. You can get a landing permit on arrival at Delhi or Kolkata airport by emailing firstname.lastname@example.org or calling + 91 2301 4104 in advance. Permits are valid for 2 weeks and can’t be renewed.