Some trading platforms really abuse trading volume. This is mainly done by young exchanges that want to achieve an influx of users due to the high volume of trading. Maybe large and well-known sites, also engaged in similar earlier.
Old exchanges highly manipulated trading volume, not they are young exchanges because i saw that from almost 3-4 years in the crypto space. I have experienced about some exchanges those are huge daily trade volume according to coinmarketcap. I am talking about
https://exrates.me/ its showing 2 million trade volume but when i am go to sell my asset than see there are no enough buy bid for sell my coin just remember that its how much manipulation.