Bitcoin's recent meteoric rise started just after China banned all exchanges in the country. The first rule of a Pump and Dump is to create scarcity. China banning exchanges means that the huge supply of Bitcoin that is produced in China dried up on the market. This scarcity will lead to a price increase. And this is what we have seen.
There is definitely a connection between Chinese exchanges and price suppression, but it goes a bit deeper than this. For years, the Chinese exchanges dictated the market price. As a trader, you had to watch Okcoin and Huobi, otherwise you would often get faked out watching western charts.
In January/February of this year, the PBOC and Chinese government began engaging in regular supervisory visits to exchanges, including in-depth audits. In reaction, the major Chinese exchanges all shut down cryptocurrency withdrawals since the investigations were apparently about capital controls. Naturally, the Bitcoin markets stopped taking cues from Chinese exchanges because it was no longer a liquid, functioning market.
It's no surprise that this is when the rally took off in earnest. I think that Okcoin and Huobi were allowing naked shorting of BTC, and that the PBOC audits ended that. After that, the low BTC supply on exchanges did the rest.