Because of the bitcoin price falling. Bitcoin price felled a lot withing a week. so why people felling panic and sold there alt-coin for getting bitcoin. I dont know when bitcoin raise again but I just believe end of the year would be good for crypto world.
Some coins were rising in price, they don't depend on BTC as heavily maybe. I mean coins as SOJ, MANNA, VTA grew 165-262% in 24 hours. But the leaders experience 2.5-13% negative change in market cap and price.