I have a problem with their solution.
Cutting down the total number of licenses implies a reduction in vehicles, but it doesn't necessarily mean that there will be an equally corresponding reduction in pollution and miles driven.
Who would be most willing to offer the highest bids? Not the people who use their vehicles the least, but the people who use their vehicles the most.
Ultimately, it will backfire because China is rapidly becoming a nation of haves and have-nots, and this market-driven solution will only emphasize the difference between the disparity of wealth -- a tax for the emerging middle class.