An eerie lull has descended as disgruntled migrant parents mull their next move after their latest high-profile campaign hardly improved the chances of their children going to a good college.

But their options may be limited, because they have been entangled in a major education policy impasse that has its roots in the nation's time-honored but outdated household registration system, or hukou. Although everyone is pursuing equal education, some are more equal than others because the hukou restrictions are intrinsically discriminatory.

Beijing, Shanghai and Guangzhou, where most of the country's top universities are located, earmark more seats for local students than those from the rest of the country. In 2011, local applicants were found to be 28-41 times more likely to be admitted to the prestigious Peking University than their counterparts from Henan, Guizhou or Anhui provinces.

To enroll in any good university, students with rural hukou will have to get a much higher score in the national college entrance examination, or gaokao, than those with a city hukou.

The issue has now become salient because migrant workers' children, who number about 20 million, cannot take gaokao in the cities where they live and study. They have to return to their native place that they left a long time ago to face fiercer competition.

The migrant parents' passionate pleas to allow their children to take gaokao with their urban peers have caused deep resentment among urban dwellers who fear losing their privileges, such as higher college admission rates, which are enshrined in the hukou system.

The case for migrants' children has been made more difficult because, if successful, it could perpetuate an already embattled college enrolment system that needs overhaul.

Even architects of gaokao have conceded that holding the same tests has not been helpful in selecting students of diverse backgrounds and abilities, and admissions based mainly on gaokao scores have led to a waste of precious time for students who spend a year just to raise a few points to surge ahead.