From the very begining Jio was offering 20MHz spectrum on this band (2.3GHz) along with 1800MHz and 850MHz band.
The reduction of 10MHz from band 2300MHz may cause slow speed on Jio LTE network.
However in Kolkata, where I took the screenshot, Jio has 30MHz of 2300MHz band. Is Jio using remaining 20MHz for LTE-Advanced or trials on 5G is on?
If I was in Mumbai I could have guess on 5G more specifically, but in Kolkata I am skeptical about it. Rather we can be on safe side - Jio is trialling for LTE-A in Kolkata.