Inequality is about the ratio of high earners to low earners. What you have linked to is a different concept, i.e. absolute income. Income inequality in china also increased, see figure 5: https://blogs.lse.ac.uk/businessreview/2019/04/01/income-ine...

Imagine you live in a neighbourhood of 50 people. Everyone starts earning more, that's absolute income increase. Then imagine your richer neighbours income has increased 100x faster than anyone else, that's income inequality.