how badly could banning of bitcoins in china affect the bitcoin market and cryptocurrency?

The answer is simple, because China is one of the largest bitcoin markets in the world. Today, however, China has reduced its influence when Japan is the largest bitcoin market.
Seventy percent of the world's bitcoin is dug from China, making China the world's largest bitcoin market. Bitcoin China shut down after the announcement, its trading platform bitcoin, Litecoin currency and other virtual currencies have dropped significantly.