I've recently started crawling for BitTorrent trackers on a few ports (69, 80, 6969) and got the following picture from the results:

Why are there so many trackers located in India? I would've expected to see a lot more in the US or Europe. There are probably other ports I should look into (if you have any suggestions please leave a comment) but it was unexpected to find so many results in India. I posed the question to Twitter and @jupenur came to the rescue:

@achillean Most of the IPs are from broadmax.in, an ISP that offers "Transparent Torrent Caching locally, for Super High Speed On Torrents."

— Juho Nurminen (@jupenur) September 4, 2015

Broadmax is an ISP primarily serving the city of Mumbai and as seen above advertises their ability to cache torrents/ improve download speeds. I've never seen this sort of thing by an ISP in the United States but it's actually been around for a while. There's even an official cache discovery protocol to help ISPs know which torrents are popular and should be cached. From a technical perspective, it makes a lot of sense actually for ISPs to locally cache the data. BitTorrent accounts for ~3.35% of the worldwide Internet traffic (2013 data), with certain countries being significantly higher such as the US at ~25%. I don't expect torrent caching to show up anytime soon in my area though. Either way, I'll be adding more ports to track whether more ISPs around the world are starting to use this sort of technology.