I think Bitcoin fees have reduced recently. Is it due to Segwit?
They ARE reducing, only about 29,000 transactions in the mempool now, down from over 200,000 in mid December:
https://dedi.jochen-hoenicke.de/queue/#24hI think two things are happening. Bitcoin's price was at an all time high in mid December and a lot of those transactions were from people hurriedly sending coins to the exchanges to cash out. Now that the price has fallen, people are hodling again.
Also - I'm pretty sure a large exchange has started batching transactions. It might be Coinbase, who announced in early Jan that they were looking at doing this. In December about 50% of the mempool was just Coinbase and GDAX transactions, so if they're batching, that's a big reason the mempool has cleared.,