Firstly, many companies are delisted for not meeting the requisites of NASDAQ. These requisites are not really thought, but there seems to be a strong cultural problem on how China understand the concept of rising capital compared to US. An average Chinese distrust anything that looks too good, or even minimally good. The listings are oftentimes based on inaccurate information (to say it softly). Not that many western companies do not ever lie - misleading information is all over - we are talking about plainly cooking the figures for sales, growth, etc...
Secondly and more recently, the Chinese government has taken direct actions on recently listed companies that have caused significant drops in valuation, directly burning any investor.
It seems that China is decoupling its economy from foreign funds, but also NASDAQ is de-listing when they fail to meet reporting and honest information requirements.
(source The Economist and other outlets).
https://www.ft.com/content/0dd3f1b4-705a-4ea4-9ade-3e105b4cfe1f
The probe by the Cyberspace Administration of China was announced two days after Didi’s July $4.4bn initial public offering, the biggest in the US this year. The investigation, which could last up to 10 weeks, came after the CAC asked Didi to consider delaying the IPO until after an internal review of its data security, according to people familiar with the matter.
https://www.ft.com/content/0dd3f1b4-705a-4ea4-9ade-3e105b4cfe1f