wind parks are also shooting up all l overhihina. but there are many problems left to overcome -- economic reforms aimed at moving the country away from heavy industries like steel are slow. and coal-fired plants still provide at least two-thirds of china's energy. that percentage rose steadily for years -- now it's leveled off. changes are coming to beijing, where smog is often a problem. all four of the city's coal-fired power stations have been shut down. ma jum is a well-known environmental activist in china. his work has helped spark a sea-change in the way people think here. ma: ten years ago if you'd stop a passersby, many of them would maybe say, we need to develop first. but now if you check with the citizensns, i think most of thm -- most likely the answewer wod be, you know, we need clean air, clclean water, safe foodod. reporter: thosose demands arare putting the government under pressure to deliver. the streets of beijing are now crowded with tens of thousands of shared bikes, and many factories have been shut. but the s