@nishantt6969 LCO stands for local commercial operator..I am not sure about the exact nature of their commercial agreement. While BSNL, in Pune and other cities, has mostly LCO method of operation because they simply do not have the staff or the $$ to install/maintain cables and wire up buildings. I had contacted a BSNL LCO for a BSNL FTTH connection some years back for my residential area and he mentioned they buy bandwidth from BSNL and sell connections to residents under the BSNL brand. They are also responsible for providing ONTs, installation, technical support etc to their customers. I wasn't sure about the QoS they (the LCO) would provide given BSNL's own hassles and gave it a pass.
I believe other ISPs would have a similar type of agreement. Maybe it varies from city to city.
In fact when I got my connection I had to get this LCO/non LCO bit clarified from some Airtel engineers and they confirmed it is direct with Airtel. It was a relief TBH