Doing business like China people may be cooking oil, but I don't know how many times it has been fried, and the lead content is extremely high.
Small restaurants such as food stalls, that oil, a lot of which is extracted from waste oil, will be ignored as long as they send money to certain departments regularly.
It is no problem to fry at home. People can use cooking oil for half a second a day. Just don't fry it too hard, or the food will go bad and be harmful to health. Therefore, it is generally enough to fry, and it is best not to eat fried food often. It doesn't matter whether you eat or not.