China's debt woes : not yet a "Lehman Moment"

What explains the sharp increase in the Chinese economy's indebtedness, in particular the China's onshore corporate debt? Has the overall debt burden reached a threshold where it poses a systemic risk, thereby making the economy vulnerable to a "Lehman Moment" - with disorderly unwinding of the private sector and sovereign debt? What are the short and longer term implications of China's growing debt problems on domestic economic growth and the broader global political economy? What has Beijing done to ameliorate the problem, how effective were its efforts, and what must it do to deal with this problem?