Plain English Meaning
These are the risks that come from the situation around you when you're flying or teaching — the weather, the airport, the airspace, and the condition of the aircraft itself. They are risks created by where and when the lesson happens, not by the people involved.
Full Definition
In aviation instruction, environmental risks are the hazards present in the surroundings where training takes place — including weather, terrain, airspace, traffic density, lighting conditions, runway condition, and aircraft systems status — that can affect the safety of a flight or ground lesson.