Even I observed this, check out bitcoinpricelab.com, which has a chart comparing prices of all the exchanges, HitBTC is way too much compared to the rest. In addition to this, I am quoting, the user MikeCorlene On the coinmarketcap thread
I'd like to ask for HitBTC to be removed from CoinMarketCap. They are known for faking volume and are quite probably scamming in other ways. Some references:
I think that for something as sensitive as market cap it's important not to use exchanges that can artificially shift the market cape and trade volume.