(Yicai Global) Dec. 26 -- Some 94 percent of China's problematic after school training centers have resolved their issues and are now operating within regulations.

A total 256,691 institutions have taken special corrective measures since a Ministry of Education report revealed that 272,842 out of 401,050 centers spanning 2,963 cities and districts, the watchdog said in its latest report on Dec. 24.

While the centers have made the necessary initial changes, it is important that they continue to adhere to the heightened standards, the ministry said. The requirements are largely based around the conditions of premises, faculty and management.

After school centers have been growing rapidly in recent years. The sector was worth around CNY800 billion (USD116 billion) in 2016, with classes attended 137 million times and around eight million teachers working at the institutions.

Extra-curricular, or shadow education, is a common practice in China, but is getting a bad rep for overloading students in their free time and disturbing learning at school. The education and other ministries have issued five notices soliciting opinions on the subject since February and the issue has been the primary focus for the country's education sector throughout the year.