I think you failed to emphasise a very key word here, the last MAJOR coal fired power plant is closing. So it's not the last one around. Just a bullshit PR stunt
It also states "It marked the proportion of electricity generated in Beijing by clean energy reached 100 percent."
The part that should be emphasized is correct: the point is that the last coal power plant in BEIJING was shut down, which means nothing if you are surrounded on all sides by some of the worst coal polluters in China