I lived in china and still travel there a lot. There are third party measurements to air pollution stats and they tell the same story as the official stats. And plus we can see it from their own eyes. The air quality in Beijing in recent years is much better than before. Actually environmental policy is a interesting one. A lot of air pollution comes from private factories, steel mills and coal factories etc. If you talk to a lot of middle to low income Chinese people, they couldnt care less about the air quality and would love to continue to produce the previous way and earn money. If it was a rule of majority, I doubt the air quality in China would improve as quick. What the government did was implement strict emission controls laws. This cause a lot of people I know discontent, but the government also provided subsidies and other policies to help polluting industries to improve. Now, looking at the sky the smog issues is much less, there has being big impact to the industries but the economy still grew indicating that the polluting industries has evolved.I think a lot of people are now happier. And people dont get locked up for having benign comments on wechat, I criticize the ccp and government all the time. But if you spread rumors online and spread anti-government messages like "death to president", "fuck the ccp and lets revolution" or something, you can get banned or worse gets a talked by the police or a 15 day detention (this is based on anti-rumor law). And no you dont get locked up or disappeared or sent to "Concentration camps". As to why the government is so paranoid about this, China does not have a stable political system yet. The political system I mean the entire government structure, in the US that is the legislative branch (congress), executive branch (the white house), the legal branch (supreme court). In the US we criticize the president and the members of congress but we rarely criticize the legitimacy of congress the white house the supreme court. The system forms the long term stable governing body in the states. It allows people to voice their demands, government to internalize the demands, and resolve societal conflicts. In China the governance system is not as established, the ccp and government is still trying to find a stable long term governing structure. People have to understand China is very diverse, I say more geopolitically diverse than the US. In the US while people comes from all over the world, people are united by common political ideologies and common language (english). They are also too spread out in geography to be a political force in elections. In China, each region has a different demographic mix, its own sense of belonging, and its own dialect of Chinese that has completely different pronunciations. Contrary to popular belief, there are a lot of beneficial policies to minority races in China including affirmative action policies, some Han people are discontent about the preferential treatment. In an environment like this, is a lot easier for populism to take place, and for one group could gain political power and enact policies to discriminate against the other group. Conflict between groups might cause the country to break apart. We can see this issue in democratic nations as well, like recently in India with the citizenship bill. (I know people now wants to talk about xinjiang but it would be another massive debate). Many people in China do not feel the US model is able to govern China that is why China is trying to come up its own model. As for freedom speech, in China there is more emphasis on the responsibility when you speak in public setting. If its a legitimate issue, you can speak out, there has been many law and policy changes due to people speaking out. But if you are spreading purely hateful speech with no reasoning and argument to back it up, or cause social unrest, the social platform (wechat) might censor you.