Mike Hearn said the following:
The reason the true limit seems to be 700 kilobytes instead of the theoretical 1000 is that sometimes miners produce blocks smaller than allowed and even empty blocks, despite that there are lots of transactions waiting to confirm — this seems to be most frequently caused by interference from the Chinese “Great Firewall” censorship system.
Also, he mentioned on another occasion that the bandwidth through the GFW, is only about 50 KB/s, sometimes less. In the best scenario you can get 3 MB/s, according to Scaling Bitcoin Conference.
Mike put lots of accusations towards the Chinese regarding blockchain development, but how much of that is true and if there's some solution, what will be the solution?