Why did Hong Kong set off an immigration wave in the early 1990s?

Because Hong Kong 1997 is about to return to China, Hong Kong has been occupied by Britain for one hundred years, leaving behind many western ideas and cultures, including political and economic systems and lifestyles. Many Hong Kong people have adapted to this kind of life and like it, so they are worried that the mainland, which is different from Hong Kong after the reunification, will affect their lives and choose to emigrate to other countries. Facts have proved that "one country, two systems" is very successful, as can be seen by comparing Macao.