What is a Delisting?
A Delisting is when a Company decides to cancel its listing on a particular market and not apply to re-list on another market. This is usually because the company cannot meet the exchange's minimum requirements for price, capitalization, or liquidity. This will make the shares much harder to trade and could leave them worthless.
The company may re-enter a market in the future if their financial position improves, or if it the situation worsens, the stock may become worthless be declared of negligible value. At this point the shares will be removed.