Untreated industrial sewage in the Tengger Desert, Inner Mongolia Autonomous Region, northern China, as seen on August 29, 2014. [Photo: The Beijing News]

280 people have been questioned since July, when a central supervision group started inspections, about environmental violations in Inner Mongolia Autonomous Region.

Authorities say illegal practices were detected in 41 ecological protection zones.

362 companies that were found to have violated environmental regulations have been shut down.

Investigators found that grasslands in Hulunbeir and Erdos had been used illegally, and the national reserve for Relict gulls had almost lost its ecological function.

"Many Inner Mongolian people have not realized the critical situation of local environments, but still think it is okay because of the high-volume environment," said Zhai Qing, vice president of the supervision group.

In 2014, a company in Inner Mongolia called Ronghua Industry Trade Corporation was reported to have directly drained untreated industrial sewage in the Tengger Desert.

With its environmental protection facilities unfinished, the corporation started production without permission. From May 28, 2014 to March 6, 2015, the company discharged 187,939 tons of sewage, polluting about 180 thousand square meters of land.

Two owners of the company were arrested, and government officials in Inner Mongolia were investigated.