Four cities in China’s northeastern province of Heilongjiang were accused by the Ministry of Environmental Protection of increasing air pollution through administrative failures. “Despite a red alert for bad weather, the cities failed to enforce emergency measures to reduce emissions ... which missed the opportunity to ease pollution,” the ministry said in a statement on Tuesday. The cities of Harbin, Jiamusi, Shuangyashan and Hegang were covered in a blanket of chocking smog on October 18-20, with concentrations of hazardous particles, known as PM2.5, reaching over 400 micrograms. China’s official air quality standard is 35 micrograms, while the recommended level set by the World Health Organisation is no more than 10 micrograms. Dirty diesel trucks are now the main roadblock in smog fight, Beijing warns To combat air pollution, Beijing has issued guidelines for temporary measures to curb emissions. Some industrial plants in the steel, aluminium, cement and ceramics sectors in northern part of the country were asked to limit production by up to half during the winter. Illegal burning of crop stubble, which was believed to be the main cause of the air pollution in four cities, was detected by the ministry using remote satellite sensors during the night. The ministry also found utilisation data for crop straw in the cities had been forged. Almost 90 per cent of the data reported by Shuangyashan and 70 per cent of the numbers for Hegang for last year were found to have been exaggerated. China’s dash for gas aims to cut back deadly winter smog Some coal-fired power utilities such as plants controlled by state-backed China Huadian and Harbin Hatou Investment as well as some steel mills and coal producers were found not to be enforcing capacity cuts during red alerts. Officials at the four cities were given 20 working days to make improvement plans, the ministry said.