Environmental protection authorities in Shandong province on Sunday cleared 25 enterprises of allegations that they disposed of polluted water by pumping it deep underground, while simultaneously vowing quicker responses to future concerns raised online.

The Shandong provincial environmental protection department said on its micro blog that it had concluded a half-year probe into more than 5,400 enterprises with water discharges in six cities in the province, including Weifang, Dong-ying and Rizhao, and that it did not uncover evidence of waste water being pumped underground.

The provincial authority published details of investigations into the 25 factories alleged to have committed the crimes, showing no evidence of their guilt.