aging population in Hong Kong

人口老化 = aging population.

In another words that means over certain % of the whole population are seniors.

As you ask why the situation is like this!
1 reason is because of in the medical and science are more advanced, more medicines to cure viruses or diseases, so people have a longer life.

Impact, in 1 way you can say that more elderly people will depend on the medical system, usually the seniors are retired, therefore, less people at work.

Solution, I could be wrong, but maybe the government needs to be prepared to provide better health and medical services, welfare and more recreational activities to cater to the aging population. Since when the aging population were young, they contritributed a lot to Hong Kong, so we gotta repay them for what they contributed.