The issue is with BSNL.
Most of the corporates use
VPN to help protect sensitive information.Since the default routes are changed and more and more corporates are using VPN from a provider,if the BSNL is not peered with the Network used by VPN servers,speed get a great hit.
I have seen lots of complain in my area.
Nothing can be done.Try avoiding VPN if it is not a requirement to work.
Or try dual VPN,Latency will take a hit,but if you do a bit a research,I would suggest Hotspot shield since it is based on AWS which is peered with BSNL and have peering with almost every network.
@varkey
@JB700
@Realme
Correct me if I am wrong.