PRC changes “employment” definition to at least 1 hour of work per week

That seems to be the standard definition most countries use, see : https://www.bls.gov/cps/definitions.htm#employed for an example. I wonder why it was different to begin with.

I think we do the same when it comes to poverty level, just change the definition and boom, most of north Americans are high middle classes and higher income families!!

This is misinformation. The definition hasn't changed for at least the past five years. [1] GPT-4 translation of the relevant paragraph:

"Our country's labor force survey also adopts the International Labour Organization's statistical standards for employment and unemployment. According to our country's laws, only those who are 16 years old and above can legally work. Hence, the employed population refers to people aged 16 and above who worked at least one hour during the reference period (usually one week) to earn labor compensation or business income. This includes employees who are on leave or temporarily not working. The unemployed population refers to those aged 16 and above who have no job but have actively sought work within the past three months and could start work within two weeks if suitable employment were available.

The use of international standards for the definitions of employment and unemployment ensures the comparability of our country's unemployment rate data with data from other countries. This is especially important today as our economy increasingly integrates into the international system. Furthermore, our labor force survey targets the permanent population aged 16 and above, regardless of whether they have registered as unemployed. It identifies employment and unemployment status according to international standards, enabling our country's unemployment rate data to reflect the actual state of the labor market more comprehensively."

[1] https://www.gov.cn/zhengce/2018-04/18/content_5283601.htm