Countries that are facing population ageing should encourage immigration. An aging population means that there are more retired people and there are fewer people working and paying taxes. As a result, working adults need to pay more taxes to the government. If more people immigrate to these countries, there will be a larger working population and the taxes they pay can be used on the health care system and to improve the infrastructures in these countries.
Is the use of on correct in the above sentence?
I wrote this so there is no source for it.