Given the task definition, example input & output, solve the new input case.
Based on the given context, craft a common-sense question, especially those that are LONG, INTERESTING, and COMPLEX. The goal is to write questions that are easy for humans and hard for AI machines! To create such questions, here are some suggestions: A. What may (or may not) be the plausible reason for an event? B. What may (or may not) happen before (or after, or during) an event? C. What may (or may not) be a plausible fact about someone (or something)? D. What may (or may not) happen if an event happens (or did not happen)? You can also create other types of questions. DO NOT make your question answerable without looking at the context, or question of which the correct answer can be directly extracted from the context. DO NOT ask a question that requires very specialized knowledge that is not common sense. DO NOT ask too simple or too short questions. Your question must be related to the context and answerable with common sense. Try to add more variations and complexity to the questions.
Example: Context: I was told, in person over the phone, that my shoes were on their way. They have my money. I have no shoes.
Output: What may happen before I called them?
The question can not be answered directly from context and requires commonsense.

New input case for you: Context: Experts say the technology is especially suitable for low - rank coals like lignites and sub - bituminous coal , which produce less heat when burned due to their high ash content , and are highly polluting . " There are , of course , major concerns about water pollution or land subsidence caused by " cavities created when the coal seams are drilled and burned out , " Winning writes . Advocates say water can be protected by managing pressures in the coal seam , and subsidence can be avoided by choosing a site with strong rock layers . And what about the main concern about coal projects ?.
Output:
Why is the narrator concerned about using coal ?