Local authorities in Lanzhou have warned residents against drinking tap water due to an outbreak of severe pollution in its water supply, prompting scenes of frantic bottled water purchases across the city's supermarkets.
An excessive amount of benzene, a highly carcinogenic chemical, has been detected in the city's water supply system, according to the local government. At one point, the benzene found in the tap water had spiked to a dangerous level 20 times what is considered to be safe.
Lanzhou, an industrial city in northwestern China, depends largely on the Yellow River for its water supply. In recent years, this city of four million has seen a wave of investment frenzy  as the state rolled out various initiatives to lift the economic standing of the underdeveloped western regions.
French water treatment company Veolia, the main water supplier in Lanzhou, told  state-run Xinhua news agency that the polluted water might be caused by local petrochemical companies.
The information office in Gansu province, where Lanzhou is the capital city, posted this  message on its official account on Twitter-like Sina Weibo:
Tap water is not suitable for Lanzhou residents to drink during the next 24 hours. Starting from 3 a.m. April 11, Lanzhou Veolia has put activated carbon into the company's sedimentation tanks to absorb organic material in an effort to dissolve the benzene. At 11 a.m. April 11, it suspended operation of the northern ditch facilities to get rid of the benzene-polluted water. During this time, water in the urban area of the city will be provided via depressurisation technics, but the water supply in Gaoping district and remote areas will be suspended. Water use in factories will be restrained. In the next 24 hours, running water will not be suitable for drinking, and other kinds of water will not be affected.
Local media reported that Lanzhou residents had complained about smelly tap water last month, but city officials claimed  the water quality was up to standards. A number of residents who spread the word of contamination back then were  labeled as “rumour-mongers” and “dealt with” according to law.
The water crisis in Lanzhou underscores the runaway pollution that has transfixed the nation as grassroots environmental activism begins to gain traction in China. In 2013, a prominent blogger and former journalist initiated  an online campaign calling for netizens to snap photos of polluted rivers in their hometown.
Lanzhou water contamination was one of the top three trending topics on Weibo as of Friday night.
The Beijing news offered this update on its official Weibo account:
【The pollution source has been cut off. Government will offer free safe water】 Lanzhou city's emergency team has narrowed down the pollution source and ordered it to be cut off. Relevant departments have been gathering bottled water and buckets of water from neighbouring areas, and these will be handed to residents via different administrative departments and organizations.
Weibo users criticized the government for allowing a non-Chinese company to manage the city's water systems. Comedian artist Zhang Gang complained :
I call on the Lanzhou government to collect safe drinking water and give it for free to citizens! It needs to give an accurate and direct answer! How embarrassing the continuous water pollution is to common folks. Can we have faith in water supply companies controlled by foreigners? Who decided to sell the water supply company to the French? Who did it? And who signed off on it?
Beijing Chuzi, a Weibo user with over half a million followers, wrote :
This is the stupidest thing the government has done. It hands over [the water service] to foreigners when it supposedly should be government-run. I suspect somebody might have profited from the deal.