Mamta, From what I was told recently by a Nepali travel agency: you need to be in person at the consulate. If you are in the Midwest, the consulates are in Chicago and Houston. You can not apply by mail, and it supposedly costs $35, takes about 3 weeks. You may want to google for the HK consulate (NOT the Chinese). I am not sure if $35 is for a single entry or a double entry transit. Sometime back, I had checked for countries requiring transit visa in HK. Ironically, apart from Nepal, they were mostly African countries. I think Afghanistan and Sri Lanka were the other South Asian countries. Nepal lai kasto lajmardo thau ma jhaareko.