There are many exchanges that are faking volume. Some reports show that there is up to 90% wrong volume reports. With market developing i am sure there will be more strict rules and penalties.
I think this is the next step in crypto for further development.
There should be some index be issued based on volume to track real volume of top 10 or top 20 exchanges who should be then monitored by some external company.
I hope also CoinMaketCap will take this issue into consideration soon enough to get some real data on smaller exchanges as well.
It would be very difficult to solve this problem especially in the crypto space, which is a free market and anyone can operate within it's jurisdiction without being questioned by any government agencies or individuals, what I meant to say is that there is no one regulation body controlling the activities of this exchanges, and there is definitely no way we can monitor all exchanges to bring out which one has fake value and those that are actually real, so I don't really think there is a solution to this problem unless we become a centralized platform.