Carbon black factories in Weifang city of Shandong province were required to suspend production during March 11-31, a document from the local Environmental Protection Bureau has showed.
The move was aimed at improving air quality. If the air quality remains bad, the term may extend, the document said.
Factories without the environmental protection certificate cannot resume production ever, the local regulator said.
The measures taken by the environment authorities has brought tremendous pressure to the carbon black supply, driving the carbon price much higher, an unnamed industry insider told media.
From 15 February to 15 March, the Ministry of Environment Protection of China carried out inspections on air quality in 18 north Chinese cities.
In December 2016, some local environment authorities already stepped in the production of carbon black factories.
For instance, Taiyuan Black Cat Carbon Black Co. started the annual overhaul earlier than scheduled after it received the notice of production suspension.
