There most definitely are environmental protection laws.  In my direct experience, some of these laws are even more stringent than those in the US.  But like you said, the following and enforcement of these laws are another issue entirely....

I saw a TV show about China. There is a city where 50% of the worlds computers end up to be recycled. Just heeps of circuit boards every where in the pics.They break the picture tubes for something. The place is totally polluted. I wonder how much of China is badly polluted.

atleast they are checking motor vehicles CO2 emissions and giving a green sticket to be affixed on the front glasss... without which u should not drive...

so yes.. laws do exist

Yes, they do exist, and are often cited as reasons China does things (or refuses to do things) which most people see as being uncooperative.

Environmental laws were cited in 2010 as a reason to stop rare earth mineral exports to Japan (though not to other countries). It had nothing to do with China throwing a tantrum over Japan arresting a Chinese fishing boat captain for illegal fishing.

Yes, they have them. Theoretically, they are some of the toughest in the world. They just never enforce them. The central government in Beijing, who are the people that set environmental policy, really can't enforce the policies that they make on their own, and the local leaders are typically uninterested in abiding by environmental laws. Think about it. If your political career were tied to producing a set amount of steal, for instance, how interested would you be from enforcing a set of regulations that are either going to make it more difficult, or completely impossible for you to meet your quota? So for practical purposes, China is essentially divided into thousands of political fiefdoms where the mayor and the heads of whatever industry or industries are important to that particular area have a lot of autonomy, even when enforcing established law. Fareed Zakaria, for instance, has argued that because power is essentially shared between a central authority and regional authorities that the Chinese system is in a way like the federal systems used by governments in North America.  The difference is that while in the US, and presumably Mexico and Canada,  the central government holds supremacy over local governments, local government in China functionally holds the power to essentially veto rules and regulations it doesn't like as they are the ones charged with enforcing environmental regulations. 

What matt said, but that 'outlook' applies to ALL laws from jaywalking to cannibalism! China has billions of laws but each province / region / city chooses which ones to enforce, and they don't tell you which ones they are.