^^The issues that govern Asian and Latin American immigrants are quite different since the former require a lengthy transoceanic trip and usually arrive by air whereas the latter need only walk or swim across the border.
Both are recently declining for very different reasons. I won't go into the Latin American issue here--it's too complicated and emotional and I don't want to add politics to this any more than necessary.
But with Asians, what we may be seeing may have to do with Trump Administration policies shutting down family-based immigration from countries that cannot or will not satisfy US vetting requirements for persons desiring to immigrate. According to the Washington Post, those policies have, at the moment "all but shut down" immigration from Myanmar, also known as Burma, as well as Nigeria, Kyrgyzstan, Eritrea, Sudan and Tanzania. Besides those countries, I have no doubt procedures in other countries have been slowed. Family-based immigration in general is not favored by the current US Administration.
See:
https://www.washingtonpost.com/natio...c09_story.html