[srisa]

This year they have come up with something called netbanking verification. With that you don't have to mail any documents even if you don't have digital signature. If I remember correctly, there are other means of verification in addition to netbanking.

[dingo_bat]

They just sent me an OTP on my phone. Thats it. Verification done. Then, as you mention, people can also log in to their net banking portal and verify, since the account would be linked to your PAN card. So in conclusion, most people should not need to send any hard copy at all.

[yati]

I took up a job outside India this year, and lost my India number. Now I just can't use the netbanking verification. I still haven't mailed the documents :/

[nmridul]

You need to convert your accounts (legally required once attaining NRI status) to NRO/NRE status and then you will receive OTP on your email. This is the case atleast with ICICI.

Previously had to close the resident account and then open new NRO/NRE accounts. But now it seems just changing the status of your old accounts and it retains the old numbers.