This article (link to the article to the 'mirror') is nonsense, most important information is missing. Rather empty talk.
How many women are there? How many of these women are young, single and working in factories?
How much is the ratio men:women in this area, nowhere any figure is mentioned.
If true other cities which are full with factories would also show up with a significant surplus of young women, but it does not seem to be like that.
The other link of the Independent is clearer, but totally sexist, and no idea if this all true or not.
The population disparity is reportedly 89 men for every 100 women because local bosses in Dongguan - a centre for manufacturing - shun male employees for more reliable female workers.
Females are more 'reliable' than men?
In all China the ratio is considered to be 118 men : 100 women.
As far as I know a real surplus of women can be found only in Latin America, like Colombia and Mexico, as there are many gang related killings going on all the time and most victims are young men. True or not, I don't know.