Environmental protection volunteers exposed two illegal hazardous waste dumps in the suburbs of Lanzhou, capital of Northwest China's Gansu province, on Monday. Thousands of cubic tons of carbon blocks and waste residue from the electrolyzing of aluminum have been buried under a thin layer of earth or piled up in the open air in two valleys near a village of 2,700 residents.

The carbon blocks, dumped by the State-owned Aluminum Corporation of China Limited's Lanzhou branch, contain large amounts of highly toxic fluoride and cyanide, which are soluble in water, contaminating the groundwater and soil.

The company has vowed to take immediate action to clean up the sites and hold accountable those responsible. But this is not the first time it has been caught illegally dumping hazardous waste.

It has been investigated and punished by the Ministry of Environmental Protection and the Lanzhou environmental protection bureau in 2013, 2015, 2016, and as recently as September, for air pollution and the improper disposal of solid industrial waste.

In September, after paying a fine and dismissing six executives, the company, which must have thought the dust had settled down, carried on dumping the waste as it did before until the volunteers exposed what they were doing in the two valleys.

The proper disposal method is to grind the toxic solid waste, mix the powder with limestone and cement and then bury the mixture deep in designated toxic waste landfills.

Although the Ministry of Environmental Protection's orders have finally been carried out by the local environmental watchdog, the government's environmental protection system has played its role without doing its job.

This shows the challenge the country faces in pursuing green development in the poorer inland areas, where the tax revenue of even the polluting enterprises remains indispensable for local governments. The local environment watchdogs turn a blind eye to pollution as long as companies pay the compulsory fines when the watchdogs are forced to act.