In the miner’s memory pools, more than 200 thousand transactions accumulated and some of these transactions remain unconfirmed more than 24 hours. Exchanges are overloaded and becoming victims of DDoS attacks. In fact, the main reason for this - the huge prices and large fluctuations that make people take their bitcoins out of wallets and send it to exchanges. What is more, BTC holders make transfers for arbitrage transactions.
For the last 24 hours, the sales of bitcoins approached $ 29 billion, which is five times more than in November. Bitcoin, traded on the stock exchanges, does not affect the blockchain, because all transactions were made outside the network. Nevertheless, the demand for crypto currency and the huge volume of trades indirectly affects the cost because users are expecting their money to be sent to and out from exchanges.
The divergent price of BTC on major exchanges theoretically creates huge arbitrage opportunities. However, in practice, no one could benefit from them because of mempool clogging. In spite of the fact, that all the new blocks have more than 1MB size, it won't be possible to eliminate the “cork” in blockchain. That happens because the percentage of using Segwit-transactions remains below 15% and there is no other way to enchance network capacity.