Today I was having a chat with my friend Hari Haran. He mentioned that Facebook has started its PoP in Mumbai. This seems true and Facebook has mentioned GPX Mumbai as their private peering PoP in their peeringdb record.

 
I triggered a quick test trace to “www.facebook.com” on IPv4 from all Indian RIPE Atlas probes and resolved “www.facebook.com” on the probe itself. The lowest latency is from Airtel Karnataka and that’s still hitting Facebook in Singapore. I do not see any of networks with probe coverage hitting Facebook node locally.
 

 
Except for a few a lot just seem to be hitting Singapore. Thus clearly there’s a huge scope of peering.
 

Full measurement results here: https://atlas.ripe.net/measurements/8777252/#!general
 
If you are an ISP in India, you can start peering with Facebook right away!