China's economic boom has managed to lift millions of people out of poverty but some parts of the country are still battling social problems, including soaring rates of drug addiction.

One of the worst-affected areas is China's southern province of Yunnan on the border with Myanmar, one of the world's biggest sources of heroin.

With a hit costing just a few cents, authorities there are fighting a losing battle to control the problem.

Al Jazeera's Tony Birtley reports. (Mar 11, 2010)