Excel Import to web application

Question

Dear Members

I'm having an asp .net web application, C# is the language. Here i'm importing bulk data from an excel file having around 5000 thousand rows. While importing , there

are some validations and calculations on it, So its taking around 10 to 15 min for each import. By the time the application gets hang as well as the user being idle.

Is there any best practice to handle such a situation ? Please guide me, it would have been a great help.

Thank you all.