Wang Haijun, 40, still becomes emotional when venturing underground. A good 18 years of his life was spent in the coal mine, and now with its closure, he has bid farewell to a part of his life as well as a workplace that was turned into history.

Datai, in southwest Beijing's Mentougou District, was the last coal mine to be shut down in the capital. As China battles with environmental pollution and pushes for green development, coal is gradually being phased out. The country is switching to more environmentally friendly energy sources and embracing renewables.

Not wanting to leave his family behind, Wang took a test that saw him admitted to Jingxi Forest Farm, a national forest farm that was built in the vicinity of the Datai coal mine. He became a forester. His life ahead is changing dramatically.