Greening, in this use, is when a person or an organisation starts to think and know more about environmental problems, and often starts to change what they do. A company that begins to measure its waste, a city that writes a plan around clean energy, a school that starts teaching pupils to care for the river — people call that greening. It is a word of process, used more in news and reports than at the dinner table. It is not the same as painting something green, and it is not only planting trees, though planting can be part of it. Though actually, Chinese 綠化 often means making a place greener with plants; this English greening is more about ideas, habits, and policy. There is also an old apple called a greening, and greening can mean turning green in colour; those are other uses. Here it is the environmental one.