An ICP license is a mandatory step for companies wishing to host their website in Mainland China. Without an ICP registration number, you will not be eligible for China-based web hosting and CDN services. Your domain also runs the risk of being blacklisted for not abiding by Chinese content laws.
Foreign companies successfully apply for an ICP license for China on a daily basis, but this is not to say that the process is easy or straightforward. This info paper will help you walk through the procedure of applying for an ICP license.